125 lines
5.0 KiB
Plaintext
125 lines
5.0 KiB
Plaintext
-- This file contains the parser, which converts Nomsu text into abstract syntax trees
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lpeg = require 'lpeg'
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re = require 're'
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lpeg.setmaxstack 10000
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{:P,:R,:S,:C,:Cmt,:Carg} = lpeg
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{:match, :sub} = string
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{:insert, :remove} = table
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files = require 'files'
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{:NomsuCode, :LuaCode, :Source} = require "code_obj"
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AST = require "nomsu_tree"
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NOMSU_DEFS = with {}
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-- Newline supports either windows-style CR+LF or unix-style LF
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.nl = P("\r")^-1 * P("\n")
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.ws = S(" \t")
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.tonumber = tonumber
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.table = -> {}
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.unpack = unpack or table.unpack
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string_escapes = n:"\n", t:"\t", b:"\b", a:"\a", v:"\v", f:"\f", r:"\r"
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digit, hex = R('09'), R('09','af','AF')
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.escaped_char = (P("\\")*S("xX")*C(hex*hex)) / => string.char(tonumber(@, 16))
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.escaped_char += (P("\\")*C(digit*(digit^-2))) / => string.char(tonumber @)
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.escaped_char += (P("\\")*C(S("ntbavfr"))) / string_escapes
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.operator_char = S("'`~!@$^&*-+=|<>?/")
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.utf8_char = (
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R("\194\223")*R("\128\191") +
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R("\224\239")*R("\128\191")*R("\128\191") +
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R("\240\244")*R("\128\191")*R("\128\191")*R("\128\191"))
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.ident_char = R("az","AZ","09") + P("_") + .utf8_char
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.userdata = Carg(1)
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.add_comment = (src,end_pos,start_pos,comment,userdata)->
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userdata.comments[start_pos] = comment
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return true
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.error = (src,end_pos,start_pos,err_msg,userdata)->
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seen_errors = userdata.errors
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if seen_errors[start_pos]
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return true
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num_errors = 0
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for _ in pairs(seen_errors) do num_errors += 1
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if num_errors >= 10
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seen_errors[start_pos+1] = colored.bright colored.yellow colored.onred "Too many errors, canceling parsing..."
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return #src+1
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err_pos = start_pos
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line_no = files.get_line_number(src, err_pos)
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--src = files.read(userdata.source.filename)
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prev_line = line_no == 1 and "" or files.get_line(src, line_no-1)
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err_line = files.get_line(src, line_no)
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next_line = files.get_line(src, line_no+1)
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i = err_pos-files.get_line_starts(src)[line_no]
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pointer = ("-")\rep(i) .. "^"
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err_msg = colored.bright colored.yellow colored.onred (err_msg or "Parse error").." at #{userdata.source.filename}:#{line_no}:"
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if #prev_line > 0 then err_msg ..= "\n"..colored.dim(prev_line)
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err_line = colored.white(err_line\sub(1, i))..colored.bright(colored.red(err_line\sub(i+1,i+1)))..colored.dim(err_line\sub(i+2,-1))
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err_msg ..= "\n#{err_line}\n#{colored.red pointer}"
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if #next_line > 0 then err_msg ..= "\n"..colored.dim(next_line)
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seen_errors[start_pos] = err_msg
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return true
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setmetatable(NOMSU_DEFS, {__index:(key)=>
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make_node = (start, value, stop, userdata)->
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if userdata.source
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with userdata.source
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value.source = Source(.filename, .start + start-1, .start + stop-1)
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setmetatable(value, AST[key])
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value.comments = userdata.comments
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if value.__init then value\__init!
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return value
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self[key] = make_node
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return make_node
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})
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Parser = {}
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NOMSU_PATTERN = do
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-- Just for cleanliness, I put the language spec in its own file using a slightly modified
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-- version of the lpeg.re syntax.
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peg_tidier = re.compile [[
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file <- %nl* version %nl* {~ (def/comment) (%nl+ (def/comment))* %nl* ~}
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version <- "--" (!"version" [^%nl])* "version" (" ")* (([0-9])+ -> set_version) ([^%nl])*
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def <- anon_def / captured_def
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anon_def <- ({ident} (" "*) ":"
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{~ ((%nl " "+ def_line?)+) / def_line ~}) -> "%1 <- %2"
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captured_def <- ({ident} (" "*) "(" {ident} ")" (" "*) ":"
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{~ ((%nl " "+ def_line?)+) / def_line ~}) -> "%1 <- (({} {| %3 |} {} %%userdata) -> %2)"
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def_line <- (err / [^%nl])+
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err <- ("(!!" { (!("!!)") .)* } "!!)") -> "(({} (%1) %%userdata) => error)"
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ident <- [a-zA-Z_][a-zA-Z0-9_]*
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comment <- "--" [^%nl]*
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]], {set_version: (v) -> Parser.version = tonumber(v), nl:NOMSU_DEFS.nl}
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peg_file = io.open("nomsu.peg")
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if not peg_file and package.nomsupath
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for path in package.nomsupath\gmatch("[^;]+")
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peg_file = io.open(path.."/nomsu.peg")
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break if peg_file
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assert(peg_file, "could not find nomsu.peg file")
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nomsu_peg = peg_tidier\match(peg_file\read('*a'))
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peg_file\close!
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re.compile(nomsu_peg, NOMSU_DEFS)
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Parser.parse = (nomsu_code, source=nil)->
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source or= nomsu_code.source
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nomsu_code = tostring(nomsu_code)
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userdata = {
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errors: {}, :source, comments: {}
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}
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tree = NOMSU_PATTERN\match(nomsu_code, nil, userdata)
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unless tree
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error "In file #{colored.blue tostring(source or "<unknown>")} failed to parse:\n#{colored.onyellow colored.black nomsu_code}"
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if type(tree) == 'number'
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return nil
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if next(userdata.errors)
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keys = [k for k,v in pairs(userdata.errors)]
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table.sort(keys)
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errors = [userdata.errors[k] for k in *keys]
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error("Errors occurred while parsing:\n\n"..table.concat(errors, "\n\n"), 0)
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tree.version = userdata.version
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return tree
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return Parser
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