c2nelua rudimentar experiment

c2nelua.lua

local re = require 'relabel'
local file = require 'pl.file'
local stringx = require 'pl.stringx'

local grammar = [[
body    <- {| line+ |}
line    <- (extern / anyline)
anyline <- linerest
linerest<- [^;]* ';' sp
sp      <- %s*
esp     <- %s+

extern <-
 ('extern' esp ctype fname
  lparen funcargs rparen) -> "function C.%2(%3): %1 <cimport'%2'> end"
   linerest cnl
funcargs <- {~ (funcarg (comma funcarg)*)? ~}
funcarg <- (ctype restrict? (name / '' -> 'x')) -> '%2: %1'
ctype <- (
    pointer /
    struct /
    primtype /
    name /
    varargs /
    %{UnhandledCtype}
  ) sp
restrict <- '__'? 'restrict' sp
varargs <- {'...'} sp
pointer <-
  ('void' sp '*' sp) -> 'pointer' /
  ('const' esp)? {~ (primtype / struct / name) sp -> '' {'*'+} ~}
struct <-
  'struct' sp name
primtype <-
  'unsigned long long int' -> 'culonglong' /
  'unsigned long long' -> 'culonglong' /
  'unsigned long int' -> 'culong' /
  'unsigned long' -> 'culong' /
  'unsigned int' -> 'cuint' /
  'unsigned short int' -> 'cushort' /
  'unsigned short' -> 'cushort' /
  'unsigned char' -> 'cuchar' /
  'long long int' -> 'clonglong' /
  'long long' -> 'clonglong' /
  'long int' -> 'clong' /
  'long double' -> 'clongdouble' /
  'long' -> 'clong' /
  'int' -> 'cint' /
  'short int' -> 'cshort' /
  'short' -> 'cshort' /
  'signed char' -> 'cschar' /
  'char' -> 'cchar' /
  'float' -> 'float32' /
  'double' -> 'float64' /
  'intptr_t' -> 'isize' /
  'int8_t' -> 'int8' /
  'int16_t' -> 'int16' /
  'int32_t' -> 'int32' /
  'int64_t' -> 'int64' /
  'uintptr_t' -> 'usize' /
  'uint8_t' -> 'uint8' /
  'uint16_t' -> 'uint16' /
  'uint32_t' -> 'uint32' /
  'uint64_t' -> 'uint64' /
  'void' -> 'void' /
  'ptrdiff_t' -> 'cptrdiff' /
  'size_t' -> 'csize' /
  'bool' -> 'boolean'
name <- '_'* {[_%w]+} sp
fname <- '_'* {[_%w]+} sp
comma <- ',' sp
lparen <- '(' sp
rparen <- ')' sp
cnl <- ''->nl
csp <- ''-> ' '
]]

local defs = {
  nl = function() return '\n' end
}

local function sortlines(text)
  local lines = stringx.split(text, '\n')
  table.sort(lines)
  return table.concat(lines, '\n')
end

local function convert(headerfile)
  local source = file.read(headerfile)
  if not source then
    error('no header found')
  end
  local sourcegrammar = grammar:gsub('SOURCEFILE', '<'..headerfile..'>')
  local pat = re.compile(sourcegrammar, defs)
  local res, _, errpos = pat:match(source)
  if not res then
    error(string.format('failed: %s', source:sub(errpos, errpos+100)))
  end
  local text = table.concat(res)
  --text = sortlines(text)
  local outfile = headerfile:gsub('%.h', '.nelua')
  file.write(outfile, text)
  print(text)
end

-- first generate preprocessed C headers using this Makefile:
--[[
CC=gcc
CFLAGS=-std=c17 -E -P -xc -
CHEADERS= \
	assert.h complex.h ctype.h errno.h \
	fenv.h float.h inttypes.h iso646.h \
	limits.h locale.h math.h setjmp.h \
	signal.h stdalign.h stdarg.h stdatomic.h \
	stdbool.h stddef.h stdint.h stdio.h \
	stdlib.h stdnoreturn.h string.h \
	tgmath.h threads.h time.h \
	uchar.h wchar.h wctype.h


all: $(CHEADERS)

%.h:
	echo '#include <$@>' | $(CC) $(CFLAGS) | sed "/^$$/d" > $@

clean:
	rm -f *.h
]]
convert('stdlib.h')
convert('string.h')
convert('stdio.h')
convert('time.h')
convert('signal.h')
convert('locale.h')
convert('errno.h')
convert('ctype.h')