Moved compatibility to lib/ and fixed path searching for .peg files.

1 files changed, 132 insertions, 0 deletions

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)