nomsu/parser.moon
2018-09-12 15:32:04 -07:00

159 lines
6.8 KiB
Plaintext

-- This file contains the parser, which converts Nomsu text into abstract syntax trees
lpeg = require 'lpeg'
re = require 're'
lpeg.setmaxstack 20000
{:P,:R,:S,:C,:Cmt,:Carg} = lpeg
{:match, :sub} = string
{:insert, :remove} = table
files = require 'files'
{:NomsuCode, :LuaCode, :Source} = require "code_obj"
AST = require "syntax_tree"
NOMSU_DEFS = with {}
-- Newline supports either windows-style CR+LF or unix-style LF
.nl = P("\r")^-1 * P("\n")
.ws = S(" \t")
.tonumber = tonumber
.table = -> {}
.unpack = unpack or table.unpack
string_escapes = n:"\n", t:"\t", b:"\b", a:"\a", v:"\v", f:"\f", r:"\r"
digit, hex = R('09'), R('09','af','AF')
.escaped_char = (P("\\")*S("xX")*C(hex*hex)) / => string.char(tonumber(@, 16))
.escaped_char += (P("\\")*C(digit*(digit^-2))) / => string.char(tonumber @)
.escaped_char += (P("\\")*C(S("ntbavfr"))) / string_escapes
.operator_char = S("'`~!@$^&*+=|<>?/-")
.utf8_char = (
R("\194\223")*R("\128\191") +
R("\224\239")*R("\128\191")*R("\128\191") +
R("\240\244")*R("\128\191")*R("\128\191")*R("\128\191"))
.ident_char = R("az","AZ","09") + P("_") + .utf8_char
.userdata = Carg(1)
.add_comment = (src,end_pos,start_pos,comment,userdata)->
userdata.comments[start_pos] = comment
return true
.error = (src,end_pos,start_pos,err_msg,userdata)->
seen_errors = userdata.errors
if seen_errors[start_pos]
return true
num_errors = 0
for _ in pairs(seen_errors) do num_errors += 1
if num_errors >= 10
seen_errors[start_pos+1] = colored.bright colored.yellow colored.onred "Too many errors, canceling parsing..."
return #src+1
err_pos = start_pos
line_no = files.get_line_number(src, err_pos)
--src = files.read(userdata.source.filename)
prev_line = line_no == 1 and nil or files.get_line(src, line_no-1)
err_line = files.get_line(src, line_no)
next_line = files.get_line(src, line_no+1)
i = err_pos-files.get_line_starts(src)[line_no]
j = i + (end_pos-start_pos)
pointer = ("-")\rep(i) .. "^"
err_msg = colored.bright colored.yellow colored.onred (err_msg or "Parse error").." at #{userdata.source.filename}:#{line_no}:"
if prev_line then err_msg ..= "\n"..colored.dim(prev_line)
if err_line
err_line = colored.white(err_line\sub(1, i))..colored.bright(colored.red(err_line\sub(i+1,j+1)))..colored.dim(err_line\sub(j+2,-1))
err_msg ..= "\n#{err_line}\n#{colored.red pointer}"
if next_line then err_msg ..= "\n"..colored.dim(next_line)
seen_errors[start_pos] = err_msg
return true
setmetatable(NOMSU_DEFS, {__index:(key)=>
make_node = (start, value, stop, userdata)->
if userdata.source
with userdata.source
value.source = Source(.filename, .start + start-1, .start + stop-1)
setmetatable(value, AST[key])
if value.__init then value\__init!
return value
self[key] = make_node
return make_node
})
Parser = {version:3, 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* {~ (def/comment) (%nl+ (def/comment))* %nl* ~}
def <- anon_def / captured_def
anon_def <- ({ident} (" "*) ":"
{~ ((%nl " "+ def_line?)+) / def_line ~}) -> "%1 <- %2"
captured_def <- ({ident} (" "*) "(" {ident} ")" (" "*) ":"
{~ ((%nl " "+ def_line?)+) / def_line ~}) -> "%1 <- (({} {| %3 |} {} %%userdata) -> %2)"
def_line <- (err / [^%nl])+
err <- ("(!!" { (!("!!)") .)* } "!!)") -> "(({} (%1) %%userdata) => error)"
ident <- [a-zA-Z_][a-zA-Z0-9_]*
comment <- "--" [^%nl]*
]]
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)
_anon_chunk = 0
Parser.parse = (nomsu_code, source=nil, version=nil)->
source or= nomsu_code.source
nomsu_code = tostring(nomsu_code)
unless source
source = Source("anonymous chunk ##{_anon_chunk}", 1, #nomsu_code)
_anon_chunk += 1
version or= nomsu_code\match("^#![^\n]*nomsu[ ]+-V[ ]*([0-9.]+)")
syntax_version = version and tonumber(version\match("^[0-9]+")) or Parser.version
userdata = {
errors: {}, :source, comments: {}
}
tree = Parser.patterns[syntax_version]\match(nomsu_code, nil, userdata)
if not tree or type(tree) == 'number'
error "In file #{colored.blue tostring(source or "<unknown>")} failed to parse:\n#{colored.onyellow colored.black nomsu_code}"
if next(userdata.errors)
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 (v#{syntax_version}):\n\n"..table.concat(errors, "\n\n"), 0)
comments = [{comment:c, pos:p} for p,c in pairs(userdata.comments)]
-- Sort in descending order so we can pop the first comments off the end one at a time
table.sort comments, (a,b)-> a.pos > b.pos
comment_i = 1
walk_tree = (t)->
export comment_i
comment_buff = {}
while comments[#comments] and comments[#comments].pos <= t.source.start
table.insert(comment_buff, table.remove(comments))
for x in *t
if AST.is_syntax_tree x
walk_tree x
while comments[#comments] and comments[#comments].pos <= t.source.stop
table.insert(comment_buff, table.remove(comments))
t.comments = comment_buff if #comment_buff > 0
walk_tree tree
return tree
Parser.is_operator = (s)->
return not not (NOMSU_DEFS.operator_char^1 * -1)\match(s)
Parser.is_identifier = (s)->
return not not (NOMSU_DEFS.ident_char^1 * -1)\match(s)
inline_escaper = re.compile "{~ (%utf8_char / ('\"' -> '\\\"') / ('\n' -> '\\n') / ('\t' -> '\\t') / ('\b' -> '\\b') / ('\a' -> '\\a') / ('\v' -> '\\v') / ('\f' -> '\\f') / ('\r' -> '\\r') / ('\\' -> '\\\\') / ([^ -~] -> escape) / .)* ~}", {utf8_char: NOMSU_DEFS.utf8_char, escape:(=> ("\\%03d")\format(@byte!))}
Parser.inline_escape = (s)->
return inline_escaper\match(s)
escaper = re.compile "{~ (%utf8_char / ('\\' -> '\\\\') / [\n\r\t -~] / (. -> escape))* ~}", {utf8_char: NOMSU_DEFS.utf8_char, escape:(=> ("\\%03d")\format(@byte!))}
Parser.escape = (s)->
return escaper\match(s)
return Parser