From be06fc096aa28358914bd6a76b4ea380a04b8873 Mon Sep 17 00:00:00 2001
From: Bruce Hill <bitbucket@bruce-hill.com>
Date: Sun, 15 Jul 2018 19:41:22 -0700
Subject: Major changes to how versioning and parsing work. This should be a
 better path going forward to handling upgrades. Old syntax files will stick
 around for compatibility purposes. Old syntax can be parsed into valid syntax
 trees via the old syntax (.peg) files, and then old syntax trees should be
 valid and can be upgraded via the normal code path. This change has lots of
 improvements to Nomsu codegen too.

---
 parser.moon | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

(limited to 'parser.moon')

diff --git a/parser.moon b/parser.moon
index 96f6b6c..39ad93a 100644
--- a/parser.moon
+++ b/parser.moon
@@ -73,13 +73,12 @@ setmetatable(NOMSU_DEFS, {__index:(key)=>
     return make_node
 })
 
-Parser = {}
-NOMSU_PATTERN = do
+Parser = {version:2, patterns:{}}
+do
     -- Just for cleanliness, I put the language spec in its own file using a slightly modified
     -- version of the lpeg.re syntax.
     peg_tidier = re.compile [[
-    file <- %nl* version %nl* {~ (def/comment) (%nl+ (def/comment))* %nl* ~}
-    version <- "--" (!"version" [^%nl])* "version" (" ")* (([0-9])+ -> set_version) ([^%nl])*
+    file <- %nl* {~ (def/comment) (%nl+ (def/comment))* %nl* ~}
     def <- anon_def / captured_def
     anon_def <- ({ident} (" "*) ":"
         {~ ((%nl " "+ def_line?)+) / def_line ~}) -> "%1 <- %2"
@@ -89,24 +88,27 @@ NOMSU_PATTERN = do
     err <- ("(!!" { (!("!!)") .)* } "!!)") -> "(({} (%1) %%userdata) => error)"
     ident <- [a-zA-Z_][a-zA-Z0-9_]*
     comment <- "--" [^%nl]*
-    ]], {set_version: (v) -> Parser.version = tonumber(v), nl:NOMSU_DEFS.nl}
-    peg_file = io.open("nomsu.peg")
-    if not peg_file and package.nomsupath
-        for path in package.nomsupath\gmatch("[^;]+")
-            peg_file = io.open(path.."/nomsu.peg")
-            break if peg_file
-    assert(peg_file, "could not find nomsu.peg file")
-    nomsu_peg = peg_tidier\match(peg_file\read('*a'))
-    peg_file\close!
-    re.compile(nomsu_peg, NOMSU_DEFS)
+    ]]
+    for version=1,Parser.version
+        peg_file = io.open("nomsu.#{version}.peg")
+        if not peg_file and package.nomsupath
+            for path in package.nomsupath\gmatch("[^;]+")
+                peg_file = io.open(path.."/nomsu.#{version}.peg")
+                break if peg_file
+        assert(peg_file, "could not find nomsu .peg file")
+        nomsu_peg = peg_tidier\match(peg_file\read('*a'))
+        peg_file\close!
+        Parser.patterns[version] = re.compile(nomsu_peg, NOMSU_DEFS)
 
-Parser.parse = (nomsu_code, source=nil)->
+Parser.parse = (nomsu_code, source=nil, version=nil)->
     source or= nomsu_code.source
     nomsu_code = tostring(nomsu_code)
+    version or= nomsu_code\match("^#![^\n]*nomsu[ ]+-V[ ]*([0-9.]+)")
+    version = (version and tonumber(version)) or Parser.version
     userdata = {
         errors: {}, :source, comments: {}
     }
-    tree = NOMSU_PATTERN\match(nomsu_code, nil, userdata)
+    tree = Parser.patterns[version]\match(nomsu_code, nil, userdata)
     unless tree
         error "In file #{colored.blue tostring(source or "<unknown>")} failed to parse:\n#{colored.onyellow colored.black nomsu_code}"
     if type(tree) == 'number'
@@ -116,7 +118,7 @@ Parser.parse = (nomsu_code, source=nil)->
         keys = [k for k,v in pairs(userdata.errors)]
         table.sort(keys)
         errors = [userdata.errors[k] for k in *keys]
-        error("Errors occurred while parsing:\n\n"..table.concat(errors, "\n\n"), 0)
+        error("Errors occurred while parsing (v#{version}):\n\n"..table.concat(errors, "\n\n"), 0)
     
     tree.version = userdata.version
     return tree
-- 
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