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.

1 files changed, 26 insertions, 24 deletions

diff --git a/parser.lua b/parser.lua
index d928fc8..4689e16 100644
--- a/parser.lua
+++ b/parser.lua
@@ -110,11 +110,12 @@ setmetatable(NOMSU_DEFS, {
     return make_node
   end
 })
-local Parser = { }
-local NOMSU_PATTERN
+local Parser = {
+  version = 2,
+  patterns = { }
+}
 do
-  local peg_tidier = re.compile([[    file <- %nl* version %nl* {~ (def/comment) (%nl+ (def/comment))* %nl* ~}
-    version <- "--" (!"version" [^%nl])* "version" (" ")* (([0-9])+ -> set_version) ([^%nl])*
+  local peg_tidier = re.compile([[    file <- %nl* {~ (def/comment) (%nl+ (def/comment))* %nl* ~}
     def <- anon_def / captured_def
     anon_def <- ({ident} (" "*) ":"
         {~ ((%nl " "+ def_line?)+) / def_line ~}) -> "%1 <- %2"
@@ -124,39 +125,40 @@ do
     err <- ("(!!" { (!("!!)") .)* } "!!)") -> "(({} (%1) %%userdata) => error)"
     ident <- [a-zA-Z_][a-zA-Z0-9_]*
     comment <- "--" [^%nl]*
-    ]], {
-    set_version = function(v)
-      Parser.version = tonumber(v), {
-        nl = NOMSU_DEFS.nl
-      }
-    end
-  })
-  local peg_file = io.open("nomsu.peg")
-  if not peg_file and package.nomsupath then
-    for path in package.nomsupath:gmatch("[^;]+") do
-      peg_file = io.open(path .. "/nomsu.peg")
-      if peg_file then
-        break
+    ]])
+  for version = 1, Parser.version do
+    local peg_file = io.open("nomsu." .. tostring(version) .. ".peg")
+    if not peg_file and package.nomsupath then
+      for path in package.nomsupath:gmatch("[^;]+") do
+        peg_file = io.open(path .. "/nomsu." .. tostring(version) .. ".peg")
+        if peg_file then
+          break
+        end
       end
     end
+    assert(peg_file, "could not find nomsu .peg file")
+    local nomsu_peg = peg_tidier:match(peg_file:read('*a'))
+    peg_file:close()
+    Parser.patterns[version] = re.compile(nomsu_peg, NOMSU_DEFS)
   end
-  assert(peg_file, "could not find nomsu.peg file")
-  local nomsu_peg = peg_tidier:match(peg_file:read('*a'))
-  peg_file:close()
-  NOMSU_PATTERN = re.compile(nomsu_peg, NOMSU_DEFS)
 end
-Parser.parse = function(nomsu_code, source)
+Parser.parse = function(nomsu_code, source, version)
   if source == nil then
     source = nil
   end
+  if version == nil then
+    version = nil
+  end
   source = source or nomsu_code.source
   nomsu_code = tostring(nomsu_code)
+  version = version or nomsu_code:match("^#![^\n]*nomsu[ ]+-V[ ]*([0-9.]+)")
+  version = (version and tonumber(version)) or Parser.version
   local userdata = {
     errors = { },
     source = source,
     comments = { }
   }
-  local tree = NOMSU_PATTERN:match(nomsu_code, nil, userdata)
+  local tree = Parser.patterns[version]:match(nomsu_code, nil, userdata)
   if not (tree) then
     error("In file " .. tostring(colored.blue(tostring(source or "<unknown>"))) .. " failed to parse:\n" .. tostring(colored.onyellow(colored.black(nomsu_code))))
   end
@@ -186,7 +188,7 @@ Parser.parse = function(nomsu_code, source)
       end
       errors = _accum_0
     end
-    error("Errors occurred while parsing:\n\n" .. table.concat(errors, "\n\n"), 0)
+    error("Errors occurred while parsing (v" .. tostring(version) .. "):\n\n" .. table.concat(errors, "\n\n"), 0)
   end
   tree.version = userdata.version
   return tree