From ddef8be3df626d63f6e575d4c1416295a22371ad Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Mon, 14 Jan 2019 17:14:34 -0800
Subject: Moved compatibility to lib/ and fixed path searching for .peg files.

---
 Makefile                            |   4 +-
 compatibility/2.3.nom               |  20 ------
 compatibility/2.4.nom               |  85 -----------------------
 compatibility/2.5.5.5.nom           |  17 -----
 compatibility/2.5.nom               |  13 ----
 compatibility/2.nom                 |  38 -----------
 compatibility/3.5.5.6.nom           |  11 ---
 compatibility/3.6.nom               |  30 --------
 compatibility/3.7.nom               |  41 -----------
 compatibility/3.8.nom               |  23 -------
 compatibility/3.nom                 |  15 ----
 compatibility/4.10.12.7.nom         |  85 -----------------------
 compatibility/4.11.nom              |  97 --------------------------
 compatibility/4.12.nom              |  18 -----
 compatibility/4.8.10.nom            |  68 -------------------
 compatibility/4.9.nom               |  11 ---
 compatibility/5.13.nom              |  24 -------
 compatibility/6.14.nom              |  41 -----------
 compatibility/compatibility.nom     | 132 ------------------------------------
 compatibility/init.nom              |  19 ------
 lib/compatibility/2.3.nom           |  20 ++++++
 lib/compatibility/2.4.nom           |  85 +++++++++++++++++++++++
 lib/compatibility/2.5.5.5.nom       |  17 +++++
 lib/compatibility/2.5.nom           |  13 ++++
 lib/compatibility/2.nom             |  38 +++++++++++
 lib/compatibility/3.5.5.6.nom       |  11 +++
 lib/compatibility/3.6.nom           |  30 ++++++++
 lib/compatibility/3.7.nom           |  41 +++++++++++
 lib/compatibility/3.8.nom           |  23 +++++++
 lib/compatibility/3.nom             |  15 ++++
 lib/compatibility/4.10.12.7.nom     |  85 +++++++++++++++++++++++
 lib/compatibility/4.11.nom          |  97 ++++++++++++++++++++++++++
 lib/compatibility/4.12.nom          |  18 +++++
 lib/compatibility/4.8.10.nom        |  68 +++++++++++++++++++
 lib/compatibility/4.9.nom           |  11 +++
 lib/compatibility/5.13.nom          |  24 +++++++
 lib/compatibility/6.14.nom          |  41 +++++++++++
 lib/compatibility/compatibility.nom | 132 ++++++++++++++++++++++++++++++++++++
 lib/compatibility/init.nom          |  19 ++++++
 nomsu_environment.lua               |   2 +-
 nomsu_environment.moon              |   2 +-
 41 files changed, 792 insertions(+), 792 deletions(-)
 delete mode 100644 compatibility/2.3.nom
 delete mode 100644 compatibility/2.4.nom
 delete mode 100644 compatibility/2.5.5.5.nom
 delete mode 100644 compatibility/2.5.nom
 delete mode 100644 compatibility/2.nom
 delete mode 100644 compatibility/3.5.5.6.nom
 delete mode 100644 compatibility/3.6.nom
 delete mode 100644 compatibility/3.7.nom
 delete mode 100644 compatibility/3.8.nom
 delete mode 100644 compatibility/3.nom
 delete mode 100644 compatibility/4.10.12.7.nom
 delete mode 100644 compatibility/4.11.nom
 delete mode 100644 compatibility/4.12.nom
 delete mode 100644 compatibility/4.8.10.nom
 delete mode 100644 compatibility/4.9.nom
 delete mode 100644 compatibility/5.13.nom
 delete mode 100644 compatibility/6.14.nom
 delete mode 100644 compatibility/compatibility.nom
 delete mode 100644 compatibility/init.nom
 create mode 100644 lib/compatibility/2.3.nom
 create mode 100644 lib/compatibility/2.4.nom
 create mode 100644 lib/compatibility/2.5.5.5.nom
 create mode 100644 lib/compatibility/2.5.nom
 create mode 100644 lib/compatibility/2.nom
 create mode 100644 lib/compatibility/3.5.5.6.nom
 create mode 100644 lib/compatibility/3.6.nom
 create mode 100644 lib/compatibility/3.7.nom
 create mode 100644 lib/compatibility/3.8.nom
 create mode 100644 lib/compatibility/3.nom
 create mode 100644 lib/compatibility/4.10.12.7.nom
 create mode 100644 lib/compatibility/4.11.nom
 create mode 100644 lib/compatibility/4.12.nom
 create mode 100644 lib/compatibility/4.8.10.nom
 create mode 100644 lib/compatibility/4.9.nom
 create mode 100644 lib/compatibility/5.13.nom
 create mode 100644 lib/compatibility/6.14.nom
 create mode 100644 lib/compatibility/compatibility.nom
 create mode 100644 lib/compatibility/init.nom

diff --git a/Makefile b/Makefile
index 2497dde..be82267 100644
--- a/Makefile
+++ b/Makefile
@@ -50,7 +50,7 @@ optimize: lua $(LIB_LUA_FILES)
 .PHONY: clean
 clean:
 	@echo "\033[1mDeleting...\033[0m"
-	@rm -rvf version lib/*.lua lib/*/*.lua compatibility/*.lua
+	@rm -rvf version lib/*.lua lib/*/*.lua
 
 .PHONY: install
 install: lua version optimize
@@ -78,7 +78,7 @@ install: lua version optimize
 	&& chmod +x $$prefix/bin/nomsu$$version \
 	&& cp -v nomsu $$prefix/bin \
 	&& cp -v doc/nomsu.1 $$prefix/share/man/man1 \
-	&& cp -rv $(LUA_FILES) $(PEG_FILES) lib compatibility $$prefix/share/nomsu/$$version;
+	&& cp -rv $(LUA_FILES) $(PEG_FILES) lib $$prefix/share/nomsu/$$version;
 
 .PHONY: uninstall
 uninstall: version
diff --git a/compatibility/2.3.nom b/compatibility/2.3.nom
deleted file mode 100644
index 67870ac..0000000
--- a/compatibility/2.3.nom
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <2.3 to Nomsu 2.3
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action ($a = $b) to "2.3" as ($a == $b)
-upgrade action (<- $) to "2.3" as (set $)
-upgrade action (assign $) to "2.3" as (set $)
-upgrade action ($a <- $b) to "2.3" as ($a = $b)
-upgrade action (external $a <- $b) to "2.3" as (external $a = $b)
-upgrade action ($a +<- $b) to "2.3" as ($a += $b)
-upgrade action ($a -<- $b) to "2.3" as ($a -= $b)
-upgrade action ($a *<- $b) to "2.3" as ($a *= $b)
-upgrade action ($a /<- $b) to "2.3" as ($a /= $b)
-upgrade action ($a ^<- $b) to "2.3" as ($a ^= $b)
-upgrade action ($a and<- $b) to "2.3" as ($a and= $b)
-upgrade action ($a or<- $b) to "2.3" as ($a or= $b)
diff --git a/compatibility/2.4.nom b/compatibility/2.4.nom
deleted file mode 100644
index e0d2e02..0000000
--- a/compatibility/2.4.nom
+++ /dev/null
@@ -1,85 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <2.4 to Nomsu 2.4
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade $tree to "2.4" as:
-    unless ($tree is "Action" syntax tree): return
-    if $tree.stub is:
-        "when" "if":
-            if ((size of $tree) == 3): return $tree
-            $conditions = []
-            $new_lines = []
-            $body =
-                ($tree.2 upgraded) if ($tree.2 is "Block" syntax tree) else [$tree.2 upgraded]
-            
-            for $line in $body:
-                when:
-                    (not ($line is "Action" syntax tree)):
-                        $new_lines, add $line
-                    
-                    ($line.stub is "*"):
-                        if ((size of $line) == 2):
-                            $conditions, add $line.2
-                        ..else:
-                            $new_lines, add $line
-                    
-                    ($line.stub == "* else"):
-                        $new_lines, add (\(else $block) with vars {.block = $line.3})
-                    
-                    else:
-                        $conditions, add $line.2
-                        $action = $line.3
-                        unless ($action is "Block" syntax tree):
-                            $action = (=lua "SyntaxTree{type='Block', source=\$action.source, \$action}")
-                        $conditions, add $action
-                        $new_lines, add
-                            =lua ("
-                                SyntaxTree{type='Action', source=\$conditions[1].source, unpack(\$conditions)}
-                            ")
-                        $conditions = []
-            
-            return
-                \(when $body) with vars {
-                    .body =
-                        =lua "SyntaxTree{type='Block', source=\$tree[2].source, unpack(\$new_lines)}"
-                }
-        
-        "if 1 is ?" "if 1 = ?":
-            $values = []
-            $new_lines = []
-            $body =
-                ($tree.5 upgraded) if ($tree.5 is "Block" syntax tree) else [$tree.5 upgraded]
-            
-            for $line in $body:
-                when:
-                    (not ($line is "Action" syntax tree)):
-                        $new_lines, add $line
-                    
-                    ($line.stub is "*"):
-                        if ((size of $line) == 2):
-                            $values, add $line.2
-                        ..else:
-                            $new_lines, add $line
-                    
-                    ($line.stub == "* else"):
-                        $new_lines, add (\(else $block) with vars {.block = $line.3})
-                    
-                    else:
-                        $values, add $line.2
-                        $action = $line.3
-                        unless ($action is "Block" syntax tree): $action = \(: $action)
-                        $values, add $action
-                        $new_lines, add
-                            =lua "SyntaxTree{type='Action', source=\$values[1].source, unpack(\$values)}"
-                        $values = []
-            
-            return
-                \(if $var is $body) with vars {
-                    .var = ($tree.2 upgraded)
-                    .body =
-                        =lua "SyntaxTree{type='Block', source=\$tree[5].source, unpack(\$new_lines)}"
-                }
diff --git a/compatibility/2.5.5.5.nom b/compatibility/2.5.5.5.nom
deleted file mode 100644
index c026a42..0000000
--- a/compatibility/2.5.5.5.nom
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <2.5.5.5 to Nomsu 2.5.5.5
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action [hash $, sha1 $] to "2.5.5.5" as
-    =lua ("
-        \(base64 decode (hash $)):gsub('.', function(c) return ('%x02'):format(c) end)
-    ")
-
-upgrade action [file with hash $] to "2.5.5.5" as
-    file with hash
-        base64
-            =lua "\$:gsub('..', function(xx) return string.char(tonumber(xx, 16)) end)"
diff --git a/compatibility/2.5.nom b/compatibility/2.5.nom
deleted file mode 100644
index 03b3f61..0000000
--- a/compatibility/2.5.nom
+++ /dev/null
@@ -1,13 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <2.5 to Nomsu 2.5
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action (for $1 where $2 matches $3 $4) to "2.5" as
-    for $1 in $2 matching $3 $4
-
-upgrade action ($1 for $2 where $3 matches $4) to "2.5" as
-    $1 for $2 in $3 matching $4
diff --git a/compatibility/2.nom b/compatibility/2.nom
deleted file mode 100644
index caf7a86..0000000
--- a/compatibility/2.nom
+++ /dev/null
@@ -1,38 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu 1 to Nomsu 2
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade $tree to "2" as:
-    unless ($tree is "Action" syntax tree): return
-    if ($tree.stub is "if 1 2 else"):
-        $true_body = ($tree.3 upgraded)
-        unless ($true_body is "Block" syntax tree):
-            $true_body = \(: $true_body)
-        $false_body = ($tree.5 upgraded)
-        unless ($false_body is "Block" syntax tree):
-            $false_body = (=lua "Block(\$false_body.source, \$false_body)")
-        
-        return
-            \(if $cond $true_body else $false_body) with vars {
-                .cond = ($tree.2 upgraded), .true_body = $true_body, .false_body = $false_body
-            }
-    
-    $need_blocks = [
-        "if", "unless", "for 1 in", "for 1 = 2 in", "repeat while 1", "repeat 1 times"
-        "repeat", "repeat until 1", "for 1 in 2 to 3 by", "for 1 in 2 to 3 via"
-        "for 1 in 2 to", "for 1 2 in", "do", "for 1 in recursive", "test", "with", "result of"
-        "when"
-    ]
-    
-    for $n in $need_blocks:
-        if ($tree.stub is $n):
-            $bits = [: for $ in $tree: add (($ upgraded) if ($ is syntax tree) else $)]
-            unless (($bits, last) is "Block" syntax tree):
-                $body = ($bits, last)
-                $bits.(size of $bits) =
-                    =lua "SyntaxTree{type='Block', source=\$body.source, \$body}"
-            return (=lua "SyntaxTree{type='Action', source=\$tree.source, unpack(\$bits)}")
diff --git a/compatibility/3.5.5.6.nom b/compatibility/3.5.5.6.nom
deleted file mode 100644
index 6528526..0000000
--- a/compatibility/3.5.5.6.nom
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <3.5.5.6 to Nomsu 3.5.5.6
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action "traceback" to "3.5.5.6" via
-    for $tree:
-        compile error at $tree "'traceback' has been deprecated."
diff --git a/compatibility/3.6.nom b/compatibility/3.6.nom
deleted file mode 100644
index 5db2aae..0000000
--- a/compatibility/3.6.nom
+++ /dev/null
@@ -1,30 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <3.6 to 3.6
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action [
-    append $item to $list, add $item to $list, to $list add $item, to $list append $item
-] to "3.6" as ($list, add $item)
-
-upgrade action [add $item to $list at index $i] to "3.6" as
-    $list, at index $i add $item
-
-upgrade action [pop from $list, remove last from $list] to "3.6" as ($list, pop)
-upgrade action [remove index $index from $list] to "3.6" as
-    $list, remove index $index
-upgrade action [to $1 write $2, $1 <-write $2] to "3.6" as ($1, add $2)
-upgrade action [to $1 write $2 joined by $3] to "3.6" as
-    $1, add $2 joined by $3
-upgrade action [declare locals in $lua] to "3.6" as ($lua, declare locals)
-upgrade action [declare locals $locs in $lua] to "3.6" as
-    $lua, declare locals $locs
-
-upgrade action [add free vars $vars to $lua] to "3.6" as
-    $lua, add free vars $vars
-
-upgrade action [remove free vars $vars from $lua] to "3.6" as
-    $lua, remove free vars $vars
diff --git a/compatibility/3.7.nom b/compatibility/3.7.nom
deleted file mode 100644
index ed877a6..0000000
--- a/compatibility/3.7.nom
+++ /dev/null
@@ -1,41 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <3.7 to 3.7
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action [$index st to last in $list] to "3.7" as
-    $list, $index st to last
-
-upgrade action [$index nd to last in $list] to "3.7" as
-    $list, $index nd to last
-
-upgrade action [$index rd to last in $list] to "3.7" as
-    $list, $index rd to last
-
-upgrade action [$index th to last in $list] to "3.7" as
-    $list, $index rd th last
-
-upgrade action [last in $list] to "3.7" as ($list, last)
-upgrade action [first in $list] to "3.7" as ($list, first)
-upgrade action [$item is in $list, $list contains $item, $list has $item] to
-.."3.7" as ($list, has $item)
-
-upgrade action [
-    $item isn't in $list, $item is not in $list, $list doesn't contain $item
-    $list does not contain $item, $list doesn't have $item, $list does not have $item
-] to "3.7" as (not ($list, has $item))
-
-upgrade action [$list has key $index, $list has index $index] to "3.7" as
-    $list.$index != (nil)
-
-upgrade action [
-    $list doesn't have key $index, $list does not have key $index
-    $list doesn't have index $index, $list does not have index $index
-] to "3.7" as ($list.$index == (nil))
-
-upgrade action [
-    number of keys in $list, len $list, || $list ||, length $list, length of $list
-] to "3.7" as (size of $list)
diff --git a/compatibility/3.8.nom b/compatibility/3.8.nom
deleted file mode 100644
index 398e3bb..0000000
--- a/compatibility/3.8.nom
+++ /dev/null
@@ -1,23 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <3.8 to 3.8 (Text method changes)
-
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-    
-upgrade action [$texts joined with $glue] to "3.8" as ($texts, joined with $glue)
-upgrade action [$texts joined, joined $texts] to "3.8" as ($texts, joined)
-upgrade action [byte $i of $text] to "3.8" as ($text, byte $i)
-upgrade action [bytes $start to $stop of $text] to "3.8" as
-    $text, bytes $start to $stop
-upgrade action [bytes of $text] to "3.8" as ($text, bytes)
-upgrade action [capitalized $text, $text capitalized] to "3.8" as
-    $text, capitalized
-upgrade action [uppercase $text, $text uppercase] to "3.8" as ($text, uppercase)
-upgrade action [
-    $text with $sub instead of $patt, $text with $patt replaced by $sub
-    $text s/ $patt / $sub
-] to "3.8" as ($text, with $patt -> $sub)
-upgrade action [$text matches $pattern] to "3.8" as ($text, matches $pattern)
-upgrade action [$text matching $pattern] to "3.8" as ($text, matching $pattern).1
diff --git a/compatibility/3.nom b/compatibility/3.nom
deleted file mode 100644
index af5c2fd..0000000
--- a/compatibility/3.nom
+++ /dev/null
@@ -1,15 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <=2 to Nomsu 3
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action (method $spec $body) to "3" as (my action $spec $body)
-upgrade action (me) to "3" as $me
-upgrade action (@) to "3" as $me
-upgrade action "as" to "3" via
-    for $tree:
-        compile error at $tree "Object API has changed and 'as' is no longer supported."
-            "Use ($obj, action ...) instead of (as $obj: action ...)"
diff --git a/compatibility/4.10.12.7.nom b/compatibility/4.10.12.7.nom
deleted file mode 100644
index c241898..0000000
--- a/compatibility/4.10.12.7.nom
+++ /dev/null
@@ -1,85 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <4.10.12.7 to 4.10.12.7
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action ($ as lua statements) to "4.10.12.7" as ($ as lua)
-upgrade action ($ as lua return) to "4.10.12.7" as
-    =lua "\$.type == 'Block' and \($ as lua) or 'return '..\($ as lua expr)"
-
-upgrade action (Lua value $) to "4.10.12.7" as (Lua $)
-
-upgrade action ($e for $ in $items) to "4.10.12.7" as [: for $ in $items: add $e]
-upgrade action ($e for $k = $v in $items) to "4.10.12.7" as
-    [: for $k = $v in $items: add $e]
-
-upgrade action ($e for $i in $start to $stop) to "4.10.12.7" as
-    [: for $i in $start to $stop: add $e]
-
-upgrade action ($e for $i in $start to $stop by $step) to "4.10.12.7" as
-    [: for $i in $start to $stop by $step: add $e]
-
-upgrade action ($e for $i in $start to $stop via $step) to "4.10.12.7" as
-    [: for $i in $start to $stop by $step: add $e]
-
-upgrade action ($k = $v for $ in $items) to "4.10.12.7" as {
-    : for $ in $items:
-        add $k = $v
-}
-
-upgrade action ($k = $v for $k0 = $v0 in $items) to "4.10.12.7" as
-    {: for $k0 = $v0 in $items: add $k = $v}
-
-upgrade action ($k = $v for $i in $start to $stop) to "4.10.12.7" as
-    {: for $i in $start to $stop: add $k = $v}
-
-upgrade action ($k = $v for $i in $start to $stop by $step) to "4.10.12.7" as
-    {: for $i in $start to $stop by $step: add $k = $v}
-
-upgrade action ($k = $v for $i in $start to $stop via $step) to "4.10.12.7" as
-    {: for $i in $start to $stop by $step: add $k = $v}
-
-upgrade action (parse $text from $filename) to "4.10.12.7" as
-    (NomsuCode from (Source $filename 1 (size of $text)) $text) parsed
-
-upgrade action ($ as lua statements) to "4.10.12.7" as ($ as lua)
-upgrade action (compile error at $pos $err hint $hint) to "4.10.12.7" as
-    compile error at $pos $err $hint
-
-# In old code, it was okay to have imports at the top of the file in the same chunk,
-    but changes to the API now require imports to be in their own file chunk in order
-    for compilation to work properly.
-upgrade $tree to "4.10.12.7" as:
-    if ($tree.type == "FileChunks"):
-        $first_chunk = $tree.1
-        $i = 1
-        $has_use = (no)
-        repeat while ($i <= (size of $first_chunk)):
-            if (($first_chunk.$i.type == "Action") and ($first_chunk.$i.stub == "use")):
-                $has_use = (yes)
-            ..else:
-                if $has_use:
-                    go to (insert chunk)
-            $i += 1
-        return
-        --- (insert chunk) ---
-        [$chunk1, $chunk2] = [
-            SyntaxTree {.type = "Block", .source = $first_chunk.source}
-            SyntaxTree {.type = "Block", .source = $first_chunk.source}
-        ]
-        
-        for $j in 1 to ($i - 1):
-            $chunk1.$j = $first_chunk.$j
-        
-        for $j in $i to (size of $first_chunk):
-            $chunk2.($j - $i + 1) = $first_chunk.$j
-        
-        $new_tree =
-            SyntaxTree {.source = $tree.source, .type = "FileChunks"} $chunk1 $chunk2
-        
-        for $i in 2 to (size of $tree):
-            $new_tree.($i + 1) = $tree.$i
-        
-        return $new_tree
diff --git a/compatibility/4.11.nom b/compatibility/4.11.nom
deleted file mode 100644
index 24dbbdc..0000000
--- a/compatibility/4.11.nom
+++ /dev/null
@@ -1,97 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <4.11 to Nomsu 4.11
-    (overhaul of function literals, deleting (if all of ...), etc. shorthand)
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-# Overhaul of function literals:
-upgrade action "call 1 with" to "4.11" via
-    for ($tree $end_version):
-        $tree2 = {.type = "Action", .source = $tree.source, .1 = $tree.2}
-        for $arg in $tree.4 at $i:
-            $tree2.($i + 1) = $arg
-        return (SyntaxTree $tree2)
-upgrade action (-> $yield_value) to "4.11" as (yield $yield_value)
-
-# Replace set {$x:1, $y:2} with [$x, $y] = [1, 2]
-upgrade action "set" to "4.11" via
-    for ($tree $end_version):
-        [$lhs, $rhs] = [\[], \[]]
-        $lhs.source = $tree.2.source
-        $rhs.source = $tree.2.source
-        for $entry in $tree.2 at $i:
-            $lhs.$i = $entry.1
-            $rhs.$i = $entry.2
-        
-        return
-            SyntaxTree {.type = "Action", .source = $tree.source} $lhs "=" $rhs
-
-upgrade action "1 with 2 ~>" to "4.11" via
-    for $tree:
-        compile error at $tree "This method has been deprecated."
-            "Perhaps this could be use ($tree, map ...) instead."
-
-# Changing filesystem API:
-upgrade action (for file $f in $path $body) to "4.11" as
-    for $f in (files for $path) $body
-
-upgrade action ($expr for file $f in $path) to "4.11" as
-    [: for $f in (files for $path): add $expr]
-
-upgrade action (line $n in $text) to "4.11" as ($text, line $n)
-upgrade action (line number of $pos in $text) to "4.11" as
-    $text, line number at $pos
-
-# Deduplicating goto labels:
-upgrade action [=== $label ===, *** $label ***] to "4.11" as (--- $label ---)
-upgrade action [===stop $label ===, ***stop $label ***] to "4.11" as
-    ---stop $label ---
-
-upgrade action [===next $label ===, ***next $label ***] to "4.11" as
-    ---next $label ---
-
-# Deprecating shorthand functions:
-upgrade action [if all of $items $body, if all of $items then $body] to "4.11" as
-    if (all of $items) $body
-
-upgrade action [unless all of $items $body, unless all of $items then $body] to
-.."4.11" as (if (not (all of $items)) $body)
-
-upgrade action [if any of $items $body, if any of $items then $body] to "4.11" as
-    if (any of $items) $body
-
-upgrade action [unless any of $items $body, unless any of $items then $body] to
-.."4.11" as (if (not (any of $items)) $body)
-
-upgrade action [if none of $items $body, if none of $items then $body] to "4.11"
-..as (if (not (any of $items)) $body)
-
-upgrade action [unless none of $items $body, unless none of $items then $body] to
-.."4.11" as (if (any of $items) $body)
-
-upgrade action [
-    if all of $items $body else $else, if all of $items then $body else $else
-] to "4.11" as (if (all of $items) $body else $else)
-
-upgrade action [
-    unless all of $items $body else $else, unless all of $items then $body else $else
-] to "4.11" as (if (not (all of $items)) $body else $else)
-
-upgrade action [
-    if any of $items $body else $else, if any of $items then $body else $else
-] to "4.11" as (if (any of $items) $body else $else)
-
-upgrade action [
-    unless any of $items $body else $else, unless any of $items then $body else $else
-] to "4.11" as (if (not (any of $items)) $body else $else)
-
-upgrade action [
-    if none of $items $body else $else, if none of $items then $body else $else
-] to "4.11" as (if (not (any of $items)) $body else $else)
-
-upgrade action [
-    unless none of $items $body else $else, unless none of $items then $body else $else
-] to "4.11" as (if (any of $items) $body else $else)
diff --git a/compatibility/4.12.nom b/compatibility/4.12.nom
deleted file mode 100644
index a76e7df..0000000
--- a/compatibility/4.12.nom
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <4.11 to Nomsu 4.11
-    (overhaul of function literals, deleting (if all of ...), etc. shorthand)
-    
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action "do next repeat" to "4.12" via
-    for $tree:
-        compile error at $tree "This method has been deprecated."
-            "Use either (do next) or (go to (label)) instead."
-
-upgrade action "stop repeating" to "4.12" via
-    for $tree:
-        compile error at $tree "This method has been deprecated."
-            "Use either (stop) or (go to (label)) instead."
diff --git a/compatibility/4.8.10.nom b/compatibility/4.8.10.nom
deleted file mode 100644
index 250dc4a..0000000
--- a/compatibility/4.8.10.nom
+++ /dev/null
@@ -1,68 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <4.8.10 to 4.8.10 (renaming "action" -> "means")
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action "local action" to "4.8.10" via
-    for ($tree $end_version):
-        $spec = $tree.3
-        $body = $tree.4
-        if $spec.type is:
-            "List":
-                if ((size of $spec) == 1):
-                    return \($spec.1 means $body)
-                ..else:
-                    return \($spec all mean $body)
-            
-            else:
-                return \($spec means $body)
-
-upgrade action "action" to "4.8.10" via
-    for ($tree $end_version):
-        $spec = $tree.2
-        $body = $tree.3
-        if $body:
-            if $spec.type is:
-                "List":
-                    if ((size of $spec) == 1):
-                        return \(externally $spec.1 means $body)
-                    ..else:
-                        return \(externally $spec all mean $body)
-                
-                else:
-                    return \(externally $spec means $body)
-        ..else:
-            return \($spec's meaning)
-
-upgrade action "compile 1 to" to "4.8.10" via
-    for ($tree $end_version):
-        $spec = $tree.2
-        $body = $tree.4
-        if $spec.type is:
-            "List":
-                if ((size of $spec) == 1):
-                    return \($spec.1 compiles to $body)
-                ..else:
-                    return \($spec all compile to $body)
-            
-            else:
-                return \($spec compiles to $body)
-
-upgrade action "parse 1 as" to "4.8.10" via
-    for ($tree $end_version):
-        $spec = $tree.2
-        $body = $tree.4
-        if $spec.type is:
-            "List":
-                if ((size of $spec) == 1):
-                    return \($spec.1 parses as $body)
-                ..else:
-                    return \($spec all parse as $body)
-            
-            else:
-                return \($spec parse as $body)
-
-upgrade action (compile as $) to "4.8.10" as (what $ compiles to)
-upgrade action (remove action $) to "4.8.10" as (($'s meaning) = (nil))
diff --git a/compatibility/4.9.nom b/compatibility/4.9.nom
deleted file mode 100644
index 14b5dd6..0000000
--- a/compatibility/4.9.nom
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <4.9 to 4.9
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action "if" to "4.9" via
-    for ($tree $end_version):
-        if ((size of $tree) > 2): return $tree
-        return \(when $tree.2)
diff --git a/compatibility/5.13.nom b/compatibility/5.13.nom
deleted file mode 100644
index 1e0db6d..0000000
--- a/compatibility/5.13.nom
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/usr/bin/env nomsu -V5.13
-#
-    This file defines upgrades from Nomsu <5.13 to 5.13
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action (size of $) to "5.13" as (#$)
-
-upgrade action "with" to "5.13" via (..)
-    for $tree:
-        $assignments = $tree.2
-        $body = $tree.3
-        if ($assignments.type != "Dict"):
-            return $tree
-        $new_assignments = \[]
-        for $a in $assignments at $i:
-            when:
-                (($a.type == "DictEntry") and ((#$a) == 1)):
-                    $a = $a.1
-                (all of [$a.type == "DictEntry", (#$a) == 2]):
-                    $a = \($a.1 = $a.2)
-            $new_assignments.$i = $a
-        return \(with $new_assignments $body)
diff --git a/compatibility/6.14.nom b/compatibility/6.14.nom
deleted file mode 100644
index 8443157..0000000
--- a/compatibility/6.14.nom
+++ /dev/null
@@ -1,41 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file defines upgrades from Nomsu <6.14 to 6.14
-use "compatibility/compatibility"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-upgrade action
-    try $action and if it succeeds $success or if it barfs $msg $fallback
-..to "6.14" as (try $action if it succeeds $success if it fails $msg $fallback)
-
-upgrade action
-    try $action and if it barfs $msg $fallback or if it succeeds $success
-..to "6.14" as (try $action if it fails $msg $fallback if it succeeds $success)
-
-upgrade action (try $action and if it barfs $fallback or if it succeeds $success)
-..to "6.14" as (try $action if it fails $fallback if it succeeds $success)
-
-upgrade action (try $action and if it barfs $msg $fallback) to "6.14" as
-    try $action if it fails $msg $fallback
-
-upgrade action (try $action and if it succeeds $success) to "6.14" as
-    try $action if it succeeds $success
-
-upgrade action (assume $assumption or barf $err) to "6.14" as
-    unless $assumption: fail $err
-
-upgrade action (barf $msg) to "6.14" as (fail $msg)
-
-upgrade action (\(1's meaning)).stub to "6.14" via
-    $tree -> (SyntaxTree {.source = $tree.source, .type = "Var", $tree.1})
-
-upgrade action (log base $b of $n) to "6.14" as (log $n base $b)
-
-upgrade action "use" to "6.14" via
-    for $tree:
-        $path = $tree.2.1
-        $path = ($path, with "%.nom$" -> "")
-        $path = ($path, with "^lib/" -> "")
-        return \(use (SyntaxTree {.source = $tree.2.source, .type="Text"} $path))
-
diff --git a/compatibility/compatibility.nom b/compatibility/compatibility.nom
deleted file mode 100644
index 444be11..0000000
--- a/compatibility/compatibility.nom
+++ /dev/null
@@ -1,132 +0,0 @@
-#!/usr/bin/env nomsu -V6.14
-#
-    This file contains code for defining ways to upgrade code between different versions
-    of Nomsu.
-    
-use "filesystem"
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-$UPGRADES = {}
-externally (upgrade to $version via $upgrade_fn) means:
-    $UPGRADES.$version = $upgrade_fn
-$ACTION_UPGRADES = ({} with fallback $ -> {})
-externally (upgrade action $stub to $version via $upgrade_fn) means:
-    $ACTION_UPGRADES.$version.$stub = $upgrade_fn
-
-(upgrade $tree to $version as $body) parses as
-    upgrade to $version via (($ $end_version) -> ($ with $tree -> $body))
-
-(upgrade action $actions to $version as $body) compiles to:
-    if ($actions is "Action" syntax tree):
-        $actions = \[$actions]
-    $lua = (Lua "")
-    for $action in $actions:
-        $replacements = {}
-        for $i in 1 to (size of $action):
-            if ($action.$i is "Var" syntax tree):
-                $replacements.($action.$i.1) = "\(\$tree as lua id)[\$i]"
-        define mangler
-        (make tree $t) means:
-            when:
-                ($t is "Var" syntax tree):
-                    if $replacements.($t.1):
-                        return $replacements.($t.1)
-                    ..else:
-                        external $needs_mangle = (yes)
-                        return ("
-                            SyntaxTree{type=\(quote $t.type), source=\(quote "\($t.source)"), \(quote (mangle $t.1))}
-                        ")
-                
-                ($t is syntax tree):
-                    $args = []
-                    for $k = $v in $t:
-                        if ((type of $k) == "number"):
-                            $args, add (make tree $v)
-                        ..else:
-                            $args, add "\($k)=\(make tree $v)"
-                    return "SyntaxTree{\($args, joined with ", ")}"
-                
-                else:
-                    return (quote $t)
-        
-        unless ("\$lua" == ""):
-            $lua, add "\n"
-        
-        $retval = (make tree $body)
-        $lua, add
-            Lua ("
-                upgrade_action_1_to_2_via(\(quote $action.stub), \($version as lua expr), function(\
-                ..\(\$tree as lua id))
-                    return \$retval
-                end)
-            ")
-    return $lua
-
-externally [
-    $tree upgraded from $start_version to $end_version
-    $tree upgraded to $end_version from $start_version
-] all mean:
-    unless ($tree is syntax tree): return $tree
-
-    ($ver as list) means (($ as number) for $ in $ver matching "[0-9]+")
-
-    (Ver $) means:
-        [$lib, $ver] = ($, match "(.*)/([0-9.]+)")
-        if $lib:
-            return {.lib = $lib, .version = ($ver as list)}
-        return {.version = ($ as list)}
-
-    $start = (Ver $start_version)
-    $end = (Ver $end_version)
-    assume $start.lib == $end.lib
-
-    $seen = {}
-    $versions = {}
-    for $v = $ in $UPGRADES: $versions.$v = (yes)
-    for $v = $ in $ACTION_UPGRADES: $versions.$v = (yes)
-    $versions = [
-        :for $v = $ in $versions:
-            if ((Ver $v).lib == $start.lib):
-                add $v
-    ]
-    
-    sort $versions by $ -> ($ as list)
-    for $ver in $versions:
-        if (($ver as list) <= $start.version): do next $ver
-        if (($ver as list) > $end.version): stop $ver
-        if $ACTION_UPGRADES.$ver:
-            $tree =
-                $tree with $ ->:
-                    if (($ is "Action" syntax tree) and $ACTION_UPGRADES.$ver.($.stub)):
-                        $with_upgraded_args = {
-                            : for $k = $v in $:
-                                add $k = ($v upgraded from $start_version to $end_version)
-                        }
-                        set $with_upgraded_args's metatable to ($'s metatable)
-                        return ($ACTION_UPGRADES.$ver.($.stub) $with_upgraded_args $end_version)
-        
-        if $UPGRADES.$ver:
-            $with_upgraded_args = {
-                : for $k = $v in $tree:
-                    add $k = ($v upgraded from $start_version to $end_version)
-            }
-            set $with_upgraded_args's metatable to ($tree's metatable)
-            $tree = ($UPGRADES.$ver $with_upgraded_args $end_version)
-    
-    if ($tree.version != $end_version):
-        $tree = (SyntaxTree {: for $k = $v in $tree: add $k = $v})
-        $tree.version = $end_version
-        if $tree.shebang:
-            $tree.shebang = "#!/usr/bin/env nomsu -V\$end_version\n"
-    
-    return $tree
-
-externally ($tree upgraded from $start_version) means
-    $tree upgraded from $start_version to (Nomsu version)
-
-externally ($tree upgraded to $end_version) means
-    $tree upgraded from ($tree.version or (Nomsu version)) to $end_version
-
-externally ($tree upgraded) means
-    $tree upgraded from ($tree.version or (Nomsu version)) to (Nomsu version)
diff --git a/compatibility/init.nom b/compatibility/init.nom
deleted file mode 100644
index 40cafff..0000000
--- a/compatibility/init.nom
+++ /dev/null
@@ -1,19 +0,0 @@
-#!/usr/bin/env nomsu -V6.14.13.8
-export "compatibility/compatibility"
-export "compatibility/2"
-export "compatibility/2.3"
-export "compatibility/2.4"
-export "compatibility/2.5"
-export "compatibility/2.5.5.5"
-export "compatibility/3"
-export "compatibility/3.5.5.6"
-export "compatibility/3.6"
-export "compatibility/3.7"
-export "compatibility/3.8"
-export "compatibility/4.8.10"
-export "compatibility/4.9"
-export "compatibility/4.10.12.7"
-export "compatibility/4.11"
-export "compatibility/4.12"
-export "compatibility/5.13"
-export "compatibility/6.14"
diff --git a/lib/compatibility/2.3.nom b/lib/compatibility/2.3.nom
new file mode 100644
index 0000000..67870ac
--- /dev/null
+++ b/lib/compatibility/2.3.nom
@@ -0,0 +1,20 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <2.3 to Nomsu 2.3
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action ($a = $b) to "2.3" as ($a == $b)
+upgrade action (<- $) to "2.3" as (set $)
+upgrade action (assign $) to "2.3" as (set $)
+upgrade action ($a <- $b) to "2.3" as ($a = $b)
+upgrade action (external $a <- $b) to "2.3" as (external $a = $b)
+upgrade action ($a +<- $b) to "2.3" as ($a += $b)
+upgrade action ($a -<- $b) to "2.3" as ($a -= $b)
+upgrade action ($a *<- $b) to "2.3" as ($a *= $b)
+upgrade action ($a /<- $b) to "2.3" as ($a /= $b)
+upgrade action ($a ^<- $b) to "2.3" as ($a ^= $b)
+upgrade action ($a and<- $b) to "2.3" as ($a and= $b)
+upgrade action ($a or<- $b) to "2.3" as ($a or= $b)
diff --git a/lib/compatibility/2.4.nom b/lib/compatibility/2.4.nom
new file mode 100644
index 0000000..e0d2e02
--- /dev/null
+++ b/lib/compatibility/2.4.nom
@@ -0,0 +1,85 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <2.4 to Nomsu 2.4
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade $tree to "2.4" as:
+    unless ($tree is "Action" syntax tree): return
+    if $tree.stub is:
+        "when" "if":
+            if ((size of $tree) == 3): return $tree
+            $conditions = []
+            $new_lines = []
+            $body =
+                ($tree.2 upgraded) if ($tree.2 is "Block" syntax tree) else [$tree.2 upgraded]
+            
+            for $line in $body:
+                when:
+                    (not ($line is "Action" syntax tree)):
+                        $new_lines, add $line
+                    
+                    ($line.stub is "*"):
+                        if ((size of $line) == 2):
+                            $conditions, add $line.2
+                        ..else:
+                            $new_lines, add $line
+                    
+                    ($line.stub == "* else"):
+                        $new_lines, add (\(else $block) with vars {.block = $line.3})
+                    
+                    else:
+                        $conditions, add $line.2
+                        $action = $line.3
+                        unless ($action is "Block" syntax tree):
+                            $action = (=lua "SyntaxTree{type='Block', source=\$action.source, \$action}")
+                        $conditions, add $action
+                        $new_lines, add
+                            =lua ("
+                                SyntaxTree{type='Action', source=\$conditions[1].source, unpack(\$conditions)}
+                            ")
+                        $conditions = []
+            
+            return
+                \(when $body) with vars {
+                    .body =
+                        =lua "SyntaxTree{type='Block', source=\$tree[2].source, unpack(\$new_lines)}"
+                }
+        
+        "if 1 is ?" "if 1 = ?":
+            $values = []
+            $new_lines = []
+            $body =
+                ($tree.5 upgraded) if ($tree.5 is "Block" syntax tree) else [$tree.5 upgraded]
+            
+            for $line in $body:
+                when:
+                    (not ($line is "Action" syntax tree)):
+                        $new_lines, add $line
+                    
+                    ($line.stub is "*"):
+                        if ((size of $line) == 2):
+                            $values, add $line.2
+                        ..else:
+                            $new_lines, add $line
+                    
+                    ($line.stub == "* else"):
+                        $new_lines, add (\(else $block) with vars {.block = $line.3})
+                    
+                    else:
+                        $values, add $line.2
+                        $action = $line.3
+                        unless ($action is "Block" syntax tree): $action = \(: $action)
+                        $values, add $action
+                        $new_lines, add
+                            =lua "SyntaxTree{type='Action', source=\$values[1].source, unpack(\$values)}"
+                        $values = []
+            
+            return
+                \(if $var is $body) with vars {
+                    .var = ($tree.2 upgraded)
+                    .body =
+                        =lua "SyntaxTree{type='Block', source=\$tree[5].source, unpack(\$new_lines)}"
+                }
diff --git a/lib/compatibility/2.5.5.5.nom b/lib/compatibility/2.5.5.5.nom
new file mode 100644
index 0000000..c026a42
--- /dev/null
+++ b/lib/compatibility/2.5.5.5.nom
@@ -0,0 +1,17 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <2.5.5.5 to Nomsu 2.5.5.5
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action [hash $, sha1 $] to "2.5.5.5" as
+    =lua ("
+        \(base64 decode (hash $)):gsub('.', function(c) return ('%x02'):format(c) end)
+    ")
+
+upgrade action [file with hash $] to "2.5.5.5" as
+    file with hash
+        base64
+            =lua "\$:gsub('..', function(xx) return string.char(tonumber(xx, 16)) end)"
diff --git a/lib/compatibility/2.5.nom b/lib/compatibility/2.5.nom
new file mode 100644
index 0000000..03b3f61
--- /dev/null
+++ b/lib/compatibility/2.5.nom
@@ -0,0 +1,13 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <2.5 to Nomsu 2.5
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action (for $1 where $2 matches $3 $4) to "2.5" as
+    for $1 in $2 matching $3 $4
+
+upgrade action ($1 for $2 where $3 matches $4) to "2.5" as
+    $1 for $2 in $3 matching $4
diff --git a/lib/compatibility/2.nom b/lib/compatibility/2.nom
new file mode 100644
index 0000000..caf7a86
--- /dev/null
+++ b/lib/compatibility/2.nom
@@ -0,0 +1,38 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu 1 to Nomsu 2
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade $tree to "2" as:
+    unless ($tree is "Action" syntax tree): return
+    if ($tree.stub is "if 1 2 else"):
+        $true_body = ($tree.3 upgraded)
+        unless ($true_body is "Block" syntax tree):
+            $true_body = \(: $true_body)
+        $false_body = ($tree.5 upgraded)
+        unless ($false_body is "Block" syntax tree):
+            $false_body = (=lua "Block(\$false_body.source, \$false_body)")
+        
+        return
+            \(if $cond $true_body else $false_body) with vars {
+                .cond = ($tree.2 upgraded), .true_body = $true_body, .false_body = $false_body
+            }
+    
+    $need_blocks = [
+        "if", "unless", "for 1 in", "for 1 = 2 in", "repeat while 1", "repeat 1 times"
+        "repeat", "repeat until 1", "for 1 in 2 to 3 by", "for 1 in 2 to 3 via"
+        "for 1 in 2 to", "for 1 2 in", "do", "for 1 in recursive", "test", "with", "result of"
+        "when"
+    ]
+    
+    for $n in $need_blocks:
+        if ($tree.stub is $n):
+            $bits = [: for $ in $tree: add (($ upgraded) if ($ is syntax tree) else $)]
+            unless (($bits, last) is "Block" syntax tree):
+                $body = ($bits, last)
+                $bits.(size of $bits) =
+                    =lua "SyntaxTree{type='Block', source=\$body.source, \$body}"
+            return (=lua "SyntaxTree{type='Action', source=\$tree.source, unpack(\$bits)}")
diff --git a/lib/compatibility/3.5.5.6.nom b/lib/compatibility/3.5.5.6.nom
new file mode 100644
index 0000000..6528526
--- /dev/null
+++ b/lib/compatibility/3.5.5.6.nom
@@ -0,0 +1,11 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <3.5.5.6 to Nomsu 3.5.5.6
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action "traceback" to "3.5.5.6" via
+    for $tree:
+        compile error at $tree "'traceback' has been deprecated."
diff --git a/lib/compatibility/3.6.nom b/lib/compatibility/3.6.nom
new file mode 100644
index 0000000..5db2aae
--- /dev/null
+++ b/lib/compatibility/3.6.nom
@@ -0,0 +1,30 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <3.6 to 3.6
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action [
+    append $item to $list, add $item to $list, to $list add $item, to $list append $item
+] to "3.6" as ($list, add $item)
+
+upgrade action [add $item to $list at index $i] to "3.6" as
+    $list, at index $i add $item
+
+upgrade action [pop from $list, remove last from $list] to "3.6" as ($list, pop)
+upgrade action [remove index $index from $list] to "3.6" as
+    $list, remove index $index
+upgrade action [to $1 write $2, $1 <-write $2] to "3.6" as ($1, add $2)
+upgrade action [to $1 write $2 joined by $3] to "3.6" as
+    $1, add $2 joined by $3
+upgrade action [declare locals in $lua] to "3.6" as ($lua, declare locals)
+upgrade action [declare locals $locs in $lua] to "3.6" as
+    $lua, declare locals $locs
+
+upgrade action [add free vars $vars to $lua] to "3.6" as
+    $lua, add free vars $vars
+
+upgrade action [remove free vars $vars from $lua] to "3.6" as
+    $lua, remove free vars $vars
diff --git a/lib/compatibility/3.7.nom b/lib/compatibility/3.7.nom
new file mode 100644
index 0000000..ed877a6
--- /dev/null
+++ b/lib/compatibility/3.7.nom
@@ -0,0 +1,41 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <3.7 to 3.7
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action [$index st to last in $list] to "3.7" as
+    $list, $index st to last
+
+upgrade action [$index nd to last in $list] to "3.7" as
+    $list, $index nd to last
+
+upgrade action [$index rd to last in $list] to "3.7" as
+    $list, $index rd to last
+
+upgrade action [$index th to last in $list] to "3.7" as
+    $list, $index rd th last
+
+upgrade action [last in $list] to "3.7" as ($list, last)
+upgrade action [first in $list] to "3.7" as ($list, first)
+upgrade action [$item is in $list, $list contains $item, $list has $item] to
+.."3.7" as ($list, has $item)
+
+upgrade action [
+    $item isn't in $list, $item is not in $list, $list doesn't contain $item
+    $list does not contain $item, $list doesn't have $item, $list does not have $item
+] to "3.7" as (not ($list, has $item))
+
+upgrade action [$list has key $index, $list has index $index] to "3.7" as
+    $list.$index != (nil)
+
+upgrade action [
+    $list doesn't have key $index, $list does not have key $index
+    $list doesn't have index $index, $list does not have index $index
+] to "3.7" as ($list.$index == (nil))
+
+upgrade action [
+    number of keys in $list, len $list, || $list ||, length $list, length of $list
+] to "3.7" as (size of $list)
diff --git a/lib/compatibility/3.8.nom b/lib/compatibility/3.8.nom
new file mode 100644
index 0000000..398e3bb
--- /dev/null
+++ b/lib/compatibility/3.8.nom
@@ -0,0 +1,23 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <3.8 to 3.8 (Text method changes)
+
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    
+upgrade action [$texts joined with $glue] to "3.8" as ($texts, joined with $glue)
+upgrade action [$texts joined, joined $texts] to "3.8" as ($texts, joined)
+upgrade action [byte $i of $text] to "3.8" as ($text, byte $i)
+upgrade action [bytes $start to $stop of $text] to "3.8" as
+    $text, bytes $start to $stop
+upgrade action [bytes of $text] to "3.8" as ($text, bytes)
+upgrade action [capitalized $text, $text capitalized] to "3.8" as
+    $text, capitalized
+upgrade action [uppercase $text, $text uppercase] to "3.8" as ($text, uppercase)
+upgrade action [
+    $text with $sub instead of $patt, $text with $patt replaced by $sub
+    $text s/ $patt / $sub
+] to "3.8" as ($text, with $patt -> $sub)
+upgrade action [$text matches $pattern] to "3.8" as ($text, matches $pattern)
+upgrade action [$text matching $pattern] to "3.8" as ($text, matching $pattern).1
diff --git a/lib/compatibility/3.nom b/lib/compatibility/3.nom
new file mode 100644
index 0000000..af5c2fd
--- /dev/null
+++ b/lib/compatibility/3.nom
@@ -0,0 +1,15 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <=2 to Nomsu 3
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action (method $spec $body) to "3" as (my action $spec $body)
+upgrade action (me) to "3" as $me
+upgrade action (@) to "3" as $me
+upgrade action "as" to "3" via
+    for $tree:
+        compile error at $tree "Object API has changed and 'as' is no longer supported."
+            "Use ($obj, action ...) instead of (as $obj: action ...)"
diff --git a/lib/compatibility/4.10.12.7.nom b/lib/compatibility/4.10.12.7.nom
new file mode 100644
index 0000000..c241898
--- /dev/null
+++ b/lib/compatibility/4.10.12.7.nom
@@ -0,0 +1,85 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <4.10.12.7 to 4.10.12.7
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action ($ as lua statements) to "4.10.12.7" as ($ as lua)
+upgrade action ($ as lua return) to "4.10.12.7" as
+    =lua "\$.type == 'Block' and \($ as lua) or 'return '..\($ as lua expr)"
+
+upgrade action (Lua value $) to "4.10.12.7" as (Lua $)
+
+upgrade action ($e for $ in $items) to "4.10.12.7" as [: for $ in $items: add $e]
+upgrade action ($e for $k = $v in $items) to "4.10.12.7" as
+    [: for $k = $v in $items: add $e]
+
+upgrade action ($e for $i in $start to $stop) to "4.10.12.7" as
+    [: for $i in $start to $stop: add $e]
+
+upgrade action ($e for $i in $start to $stop by $step) to "4.10.12.7" as
+    [: for $i in $start to $stop by $step: add $e]
+
+upgrade action ($e for $i in $start to $stop via $step) to "4.10.12.7" as
+    [: for $i in $start to $stop by $step: add $e]
+
+upgrade action ($k = $v for $ in $items) to "4.10.12.7" as {
+    : for $ in $items:
+        add $k = $v
+}
+
+upgrade action ($k = $v for $k0 = $v0 in $items) to "4.10.12.7" as
+    {: for $k0 = $v0 in $items: add $k = $v}
+
+upgrade action ($k = $v for $i in $start to $stop) to "4.10.12.7" as
+    {: for $i in $start to $stop: add $k = $v}
+
+upgrade action ($k = $v for $i in $start to $stop by $step) to "4.10.12.7" as
+    {: for $i in $start to $stop by $step: add $k = $v}
+
+upgrade action ($k = $v for $i in $start to $stop via $step) to "4.10.12.7" as
+    {: for $i in $start to $stop by $step: add $k = $v}
+
+upgrade action (parse $text from $filename) to "4.10.12.7" as
+    (NomsuCode from (Source $filename 1 (size of $text)) $text) parsed
+
+upgrade action ($ as lua statements) to "4.10.12.7" as ($ as lua)
+upgrade action (compile error at $pos $err hint $hint) to "4.10.12.7" as
+    compile error at $pos $err $hint
+
+# In old code, it was okay to have imports at the top of the file in the same chunk,
+    but changes to the API now require imports to be in their own file chunk in order
+    for compilation to work properly.
+upgrade $tree to "4.10.12.7" as:
+    if ($tree.type == "FileChunks"):
+        $first_chunk = $tree.1
+        $i = 1
+        $has_use = (no)
+        repeat while ($i <= (size of $first_chunk)):
+            if (($first_chunk.$i.type == "Action") and ($first_chunk.$i.stub == "use")):
+                $has_use = (yes)
+            ..else:
+                if $has_use:
+                    go to (insert chunk)
+            $i += 1
+        return
+        --- (insert chunk) ---
+        [$chunk1, $chunk2] = [
+            SyntaxTree {.type = "Block", .source = $first_chunk.source}
+            SyntaxTree {.type = "Block", .source = $first_chunk.source}
+        ]
+        
+        for $j in 1 to ($i - 1):
+            $chunk1.$j = $first_chunk.$j
+        
+        for $j in $i to (size of $first_chunk):
+            $chunk2.($j - $i + 1) = $first_chunk.$j
+        
+        $new_tree =
+            SyntaxTree {.source = $tree.source, .type = "FileChunks"} $chunk1 $chunk2
+        
+        for $i in 2 to (size of $tree):
+            $new_tree.($i + 1) = $tree.$i
+        
+        return $new_tree
diff --git a/lib/compatibility/4.11.nom b/lib/compatibility/4.11.nom
new file mode 100644
index 0000000..24dbbdc
--- /dev/null
+++ b/lib/compatibility/4.11.nom
@@ -0,0 +1,97 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <4.11 to Nomsu 4.11
+    (overhaul of function literals, deleting (if all of ...), etc. shorthand)
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+# Overhaul of function literals:
+upgrade action "call 1 with" to "4.11" via
+    for ($tree $end_version):
+        $tree2 = {.type = "Action", .source = $tree.source, .1 = $tree.2}
+        for $arg in $tree.4 at $i:
+            $tree2.($i + 1) = $arg
+        return (SyntaxTree $tree2)
+upgrade action (-> $yield_value) to "4.11" as (yield $yield_value)
+
+# Replace set {$x:1, $y:2} with [$x, $y] = [1, 2]
+upgrade action "set" to "4.11" via
+    for ($tree $end_version):
+        [$lhs, $rhs] = [\[], \[]]
+        $lhs.source = $tree.2.source
+        $rhs.source = $tree.2.source
+        for $entry in $tree.2 at $i:
+            $lhs.$i = $entry.1
+            $rhs.$i = $entry.2
+        
+        return
+            SyntaxTree {.type = "Action", .source = $tree.source} $lhs "=" $rhs
+
+upgrade action "1 with 2 ~>" to "4.11" via
+    for $tree:
+        compile error at $tree "This method has been deprecated."
+            "Perhaps this could be use ($tree, map ...) instead."
+
+# Changing filesystem API:
+upgrade action (for file $f in $path $body) to "4.11" as
+    for $f in (files for $path) $body
+
+upgrade action ($expr for file $f in $path) to "4.11" as
+    [: for $f in (files for $path): add $expr]
+
+upgrade action (line $n in $text) to "4.11" as ($text, line $n)
+upgrade action (line number of $pos in $text) to "4.11" as
+    $text, line number at $pos
+
+# Deduplicating goto labels:
+upgrade action [=== $label ===, *** $label ***] to "4.11" as (--- $label ---)
+upgrade action [===stop $label ===, ***stop $label ***] to "4.11" as
+    ---stop $label ---
+
+upgrade action [===next $label ===, ***next $label ***] to "4.11" as
+    ---next $label ---
+
+# Deprecating shorthand functions:
+upgrade action [if all of $items $body, if all of $items then $body] to "4.11" as
+    if (all of $items) $body
+
+upgrade action [unless all of $items $body, unless all of $items then $body] to
+.."4.11" as (if (not (all of $items)) $body)
+
+upgrade action [if any of $items $body, if any of $items then $body] to "4.11" as
+    if (any of $items) $body
+
+upgrade action [unless any of $items $body, unless any of $items then $body] to
+.."4.11" as (if (not (any of $items)) $body)
+
+upgrade action [if none of $items $body, if none of $items then $body] to "4.11"
+..as (if (not (any of $items)) $body)
+
+upgrade action [unless none of $items $body, unless none of $items then $body] to
+.."4.11" as (if (any of $items) $body)
+
+upgrade action [
+    if all of $items $body else $else, if all of $items then $body else $else
+] to "4.11" as (if (all of $items) $body else $else)
+
+upgrade action [
+    unless all of $items $body else $else, unless all of $items then $body else $else
+] to "4.11" as (if (not (all of $items)) $body else $else)
+
+upgrade action [
+    if any of $items $body else $else, if any of $items then $body else $else
+] to "4.11" as (if (any of $items) $body else $else)
+
+upgrade action [
+    unless any of $items $body else $else, unless any of $items then $body else $else
+] to "4.11" as (if (not (any of $items)) $body else $else)
+
+upgrade action [
+    if none of $items $body else $else, if none of $items then $body else $else
+] to "4.11" as (if (not (any of $items)) $body else $else)
+
+upgrade action [
+    unless none of $items $body else $else, unless none of $items then $body else $else
+] to "4.11" as (if (any of $items) $body else $else)
diff --git a/lib/compatibility/4.12.nom b/lib/compatibility/4.12.nom
new file mode 100644
index 0000000..a76e7df
--- /dev/null
+++ b/lib/compatibility/4.12.nom
@@ -0,0 +1,18 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <4.11 to Nomsu 4.11
+    (overhaul of function literals, deleting (if all of ...), etc. shorthand)
+    
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action "do next repeat" to "4.12" via
+    for $tree:
+        compile error at $tree "This method has been deprecated."
+            "Use either (do next) or (go to (label)) instead."
+
+upgrade action "stop repeating" to "4.12" via
+    for $tree:
+        compile error at $tree "This method has been deprecated."
+            "Use either (stop) or (go to (label)) instead."
diff --git a/lib/compatibility/4.8.10.nom b/lib/compatibility/4.8.10.nom
new file mode 100644
index 0000000..250dc4a
--- /dev/null
+++ b/lib/compatibility/4.8.10.nom
@@ -0,0 +1,68 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <4.8.10 to 4.8.10 (renaming "action" -> "means")
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action "local action" to "4.8.10" via
+    for ($tree $end_version):
+        $spec = $tree.3
+        $body = $tree.4
+        if $spec.type is:
+            "List":
+                if ((size of $spec) == 1):
+                    return \($spec.1 means $body)
+                ..else:
+                    return \($spec all mean $body)
+            
+            else:
+                return \($spec means $body)
+
+upgrade action "action" to "4.8.10" via
+    for ($tree $end_version):
+        $spec = $tree.2
+        $body = $tree.3
+        if $body:
+            if $spec.type is:
+                "List":
+                    if ((size of $spec) == 1):
+                        return \(externally $spec.1 means $body)
+                    ..else:
+                        return \(externally $spec all mean $body)
+                
+                else:
+                    return \(externally $spec means $body)
+        ..else:
+            return \($spec's meaning)
+
+upgrade action "compile 1 to" to "4.8.10" via
+    for ($tree $end_version):
+        $spec = $tree.2
+        $body = $tree.4
+        if $spec.type is:
+            "List":
+                if ((size of $spec) == 1):
+                    return \($spec.1 compiles to $body)
+                ..else:
+                    return \($spec all compile to $body)
+            
+            else:
+                return \($spec compiles to $body)
+
+upgrade action "parse 1 as" to "4.8.10" via
+    for ($tree $end_version):
+        $spec = $tree.2
+        $body = $tree.4
+        if $spec.type is:
+            "List":
+                if ((size of $spec) == 1):
+                    return \($spec.1 parses as $body)
+                ..else:
+                    return \($spec all parse as $body)
+            
+            else:
+                return \($spec parse as $body)
+
+upgrade action (compile as $) to "4.8.10" as (what $ compiles to)
+upgrade action (remove action $) to "4.8.10" as (($'s meaning) = (nil))
diff --git a/lib/compatibility/4.9.nom b/lib/compatibility/4.9.nom
new file mode 100644
index 0000000..14b5dd6
--- /dev/null
+++ b/lib/compatibility/4.9.nom
@@ -0,0 +1,11 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <4.9 to 4.9
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action "if" to "4.9" via
+    for ($tree $end_version):
+        if ((size of $tree) > 2): return $tree
+        return \(when $tree.2)
diff --git a/lib/compatibility/5.13.nom b/lib/compatibility/5.13.nom
new file mode 100644
index 0000000..1e0db6d
--- /dev/null
+++ b/lib/compatibility/5.13.nom
@@ -0,0 +1,24 @@
+#!/usr/bin/env nomsu -V5.13
+#
+    This file defines upgrades from Nomsu <5.13 to 5.13
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action (size of $) to "5.13" as (#$)
+
+upgrade action "with" to "5.13" via (..)
+    for $tree:
+        $assignments = $tree.2
+        $body = $tree.3
+        if ($assignments.type != "Dict"):
+            return $tree
+        $new_assignments = \[]
+        for $a in $assignments at $i:
+            when:
+                (($a.type == "DictEntry") and ((#$a) == 1)):
+                    $a = $a.1
+                (all of [$a.type == "DictEntry", (#$a) == 2]):
+                    $a = \($a.1 = $a.2)
+            $new_assignments.$i = $a
+        return \(with $new_assignments $body)
diff --git a/lib/compatibility/6.14.nom b/lib/compatibility/6.14.nom
new file mode 100644
index 0000000..8443157
--- /dev/null
+++ b/lib/compatibility/6.14.nom
@@ -0,0 +1,41 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file defines upgrades from Nomsu <6.14 to 6.14
+use "compatibility/compatibility"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+upgrade action
+    try $action and if it succeeds $success or if it barfs $msg $fallback
+..to "6.14" as (try $action if it succeeds $success if it fails $msg $fallback)
+
+upgrade action
+    try $action and if it barfs $msg $fallback or if it succeeds $success
+..to "6.14" as (try $action if it fails $msg $fallback if it succeeds $success)
+
+upgrade action (try $action and if it barfs $fallback or if it succeeds $success)
+..to "6.14" as (try $action if it fails $fallback if it succeeds $success)
+
+upgrade action (try $action and if it barfs $msg $fallback) to "6.14" as
+    try $action if it fails $msg $fallback
+
+upgrade action (try $action and if it succeeds $success) to "6.14" as
+    try $action if it succeeds $success
+
+upgrade action (assume $assumption or barf $err) to "6.14" as
+    unless $assumption: fail $err
+
+upgrade action (barf $msg) to "6.14" as (fail $msg)
+
+upgrade action (\(1's meaning)).stub to "6.14" via
+    $tree -> (SyntaxTree {.source = $tree.source, .type = "Var", $tree.1})
+
+upgrade action (log base $b of $n) to "6.14" as (log $n base $b)
+
+upgrade action "use" to "6.14" via
+    for $tree:
+        $path = $tree.2.1
+        $path = ($path, with "%.nom$" -> "")
+        $path = ($path, with "^lib/" -> "")
+        return \(use (SyntaxTree {.source = $tree.2.source, .type="Text"} $path))
+
diff --git a/lib/compatibility/compatibility.nom b/lib/compatibility/compatibility.nom
new file mode 100644
index 0000000..444be11
--- /dev/null
+++ b/lib/compatibility/compatibility.nom
@@ -0,0 +1,132 @@
+#!/usr/bin/env nomsu -V6.14
+#
+    This file contains code for defining ways to upgrade code between different versions
+    of Nomsu.
+    
+use "filesystem"
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+$UPGRADES = {}
+externally (upgrade to $version via $upgrade_fn) means:
+    $UPGRADES.$version = $upgrade_fn
+$ACTION_UPGRADES = ({} with fallback $ -> {})
+externally (upgrade action $stub to $version via $upgrade_fn) means:
+    $ACTION_UPGRADES.$version.$stub = $upgrade_fn
+
+(upgrade $tree to $version as $body) parses as
+    upgrade to $version via (($ $end_version) -> ($ with $tree -> $body))
+
+(upgrade action $actions to $version as $body) compiles to:
+    if ($actions is "Action" syntax tree):
+        $actions = \[$actions]
+    $lua = (Lua "")
+    for $action in $actions:
+        $replacements = {}
+        for $i in 1 to (size of $action):
+            if ($action.$i is "Var" syntax tree):
+                $replacements.($action.$i.1) = "\(\$tree as lua id)[\$i]"
+        define mangler
+        (make tree $t) means:
+            when:
+                ($t is "Var" syntax tree):
+                    if $replacements.($t.1):
+                        return $replacements.($t.1)
+                    ..else:
+                        external $needs_mangle = (yes)
+                        return ("
+                            SyntaxTree{type=\(quote $t.type), source=\(quote "\($t.source)"), \(quote (mangle $t.1))}
+                        ")
+                
+                ($t is syntax tree):
+                    $args = []
+                    for $k = $v in $t:
+                        if ((type of $k) == "number"):
+                            $args, add (make tree $v)
+                        ..else:
+                            $args, add "\($k)=\(make tree $v)"
+                    return "SyntaxTree{\($args, joined with ", ")}"
+                
+                else:
+                    return (quote $t)
+        
+        unless ("\$lua" == ""):
+            $lua, add "\n"
+        
+        $retval = (make tree $body)
+        $lua, add
+            Lua ("
+                upgrade_action_1_to_2_via(\(quote $action.stub), \($version as lua expr), function(\
+                ..\(\$tree as lua id))
+                    return \$retval
+                end)
+            ")
+    return $lua
+
+externally [
+    $tree upgraded from $start_version to $end_version
+    $tree upgraded to $end_version from $start_version
+] all mean:
+    unless ($tree is syntax tree): return $tree
+
+    ($ver as list) means (($ as number) for $ in $ver matching "[0-9]+")
+
+    (Ver $) means:
+        [$lib, $ver] = ($, match "(.*)/([0-9.]+)")
+        if $lib:
+            return {.lib = $lib, .version = ($ver as list)}
+        return {.version = ($ as list)}
+
+    $start = (Ver $start_version)
+    $end = (Ver $end_version)
+    assume $start.lib == $end.lib
+
+    $seen = {}
+    $versions = {}
+    for $v = $ in $UPGRADES: $versions.$v = (yes)
+    for $v = $ in $ACTION_UPGRADES: $versions.$v = (yes)
+    $versions = [
+        :for $v = $ in $versions:
+            if ((Ver $v).lib == $start.lib):
+                add $v
+    ]
+    
+    sort $versions by $ -> ($ as list)
+    for $ver in $versions:
+        if (($ver as list) <= $start.version): do next $ver
+        if (($ver as list) > $end.version): stop $ver
+        if $ACTION_UPGRADES.$ver:
+            $tree =
+                $tree with $ ->:
+                    if (($ is "Action" syntax tree) and $ACTION_UPGRADES.$ver.($.stub)):
+                        $with_upgraded_args = {
+                            : for $k = $v in $:
+                                add $k = ($v upgraded from $start_version to $end_version)
+                        }
+                        set $with_upgraded_args's metatable to ($'s metatable)
+                        return ($ACTION_UPGRADES.$ver.($.stub) $with_upgraded_args $end_version)
+        
+        if $UPGRADES.$ver:
+            $with_upgraded_args = {
+                : for $k = $v in $tree:
+                    add $k = ($v upgraded from $start_version to $end_version)
+            }
+            set $with_upgraded_args's metatable to ($tree's metatable)
+            $tree = ($UPGRADES.$ver $with_upgraded_args $end_version)
+    
+    if ($tree.version != $end_version):
+        $tree = (SyntaxTree {: for $k = $v in $tree: add $k = $v})
+        $tree.version = $end_version
+        if $tree.shebang:
+            $tree.shebang = "#!/usr/bin/env nomsu -V\$end_version\n"
+    
+    return $tree
+
+externally ($tree upgraded from $start_version) means
+    $tree upgraded from $start_version to (Nomsu version)
+
+externally ($tree upgraded to $end_version) means
+    $tree upgraded from ($tree.version or (Nomsu version)) to $end_version
+
+externally ($tree upgraded) means
+    $tree upgraded from ($tree.version or (Nomsu version)) to (Nomsu version)
diff --git a/lib/compatibility/init.nom b/lib/compatibility/init.nom
new file mode 100644
index 0000000..40cafff
--- /dev/null
+++ b/lib/compatibility/init.nom
@@ -0,0 +1,19 @@
+#!/usr/bin/env nomsu -V6.14.13.8
+export "compatibility/compatibility"
+export "compatibility/2"
+export "compatibility/2.3"
+export "compatibility/2.4"
+export "compatibility/2.5"
+export "compatibility/2.5.5.5"
+export "compatibility/3"
+export "compatibility/3.5.5.6"
+export "compatibility/3.6"
+export "compatibility/3.7"
+export "compatibility/3.8"
+export "compatibility/4.8.10"
+export "compatibility/4.9"
+export "compatibility/4.10.12.7"
+export "compatibility/4.11"
+export "compatibility/4.12"
+export "compatibility/5.13"
+export "compatibility/6.14"
diff --git a/nomsu_environment.lua b/nomsu_environment.lua
index 94e68e0..9952a65 100644
--- a/nomsu_environment.lua
+++ b/nomsu_environment.lua
@@ -35,7 +35,7 @@ local max_parser_version = 0
 for version = 1, 999 do
   local peg_file
   if package.nomsupath then
-    local pegpath = package.nomsupath:gsub("%.nom", ".peg")
+    local pegpath = package.nomsupath:gsub("lib/%?%.nom", "?.peg"):gsub("lib/%?%.lua", "?.peg")
     do
       local path = package.searchpath("nomsu." .. tostring(version), pegpath, "/")
       if path then
diff --git a/nomsu_environment.moon b/nomsu_environment.moon
index 6049555..13cf776 100644
--- a/nomsu_environment.moon
+++ b/nomsu_environment.moon
@@ -20,7 +20,7 @@ max_parser_version = 0
 for version=1,999
     local peg_file
     if package.nomsupath
-        pegpath = package.nomsupath\gsub("%.nom", ".peg")
+        pegpath = package.nomsupath\gsub("lib/%?%.nom", "?.peg")\gsub("lib/%?%.lua", "?.peg")
         if path = package.searchpath("nomsu.#{version}", pegpath, "/")
             peg_file = io.open(path)
     else
-- 
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