metalua.lua

-------------------------------------------------------------------------------
-- Copyright (c) 2006-2013 Fabien Fleutot and others.
--
-- All rights reserved.
--
-- This program and the accompanying materials are made available
-- under the terms of the Eclipse Public License v1.0 which
-- accompanies this distribution, and is available at
-- http://www.eclipse.org/legal/epl-v10.html
--
-- This program and the accompanying materials are also made available
-- under the terms of the MIT public license which accompanies this
-- distribution, and is available at http://www.lua.org/license.html
--
-- Contributors:
-- Fabien Fleutot - API and implementation
--
-------------------------------------------------------------------------------

-- Survive lack of checks
if not pcall(require, 'checks') then function package.preload.checks() function checks() end end end

-- Main file for the metalua executable
require 'metalua.loader' -- load *.mlue files
require 'metalua.compiler.globals' -- metalua-aware loadstring, dofile etc.

local alt_getopt = require 'alt_getopt'
local pp = require 'metalua.pprint'
local mlc = require 'metalua.compiler'

local M = { }

local AST_COMPILE_ERROR_NUMBER = -1
local RUNTIME_ERROR_NUMBER = -3

local alt_getopt_options = "f:l:e:o:xivaASbs"

local long_opts = {
 file='f',
 library='l',
 literal='e',
 output='o',
 run='x',
 interactive='i',
 verbose='v',
 ['print-ast']='a',
 ['print-ast-lineinfo']='A',
 ['print-src']='S',
 ['meta-bugs']='b',
 ['sharp-bang']='s',
}

local chunk_options = {
 library=1,
 file=1,
 literal=1
}

local usage=[[

Compile and/or execute metalua programs. Parameters passed to the
compiler should be prefixed with an option flag, hinting what must be
done with them: take tham as file names to compile, as library names
to load, as parameters passed to the running program... When option
flags are absent, metalua tries to adopt a "Do What I Mean" approach:

- if no code (no library, no literal expression and no file) is
 specified, the first flag-less parameter is taken as a file name to
 load.

- if no code and no parameter is passed, an interactive loop is
 started.

- if a target file is specified with --output, the program is not
 executed by default, unless a --run flag forces it to. Conversely,
 if no --output target is specified, the code is run unless ++run
 forbids it.
]]

function M.cmdline_parser(...)
 local argv = {...}
 local opts, optind, optarg =
 alt_getopt.get_ordered_opts({...}, alt_getopt_options, long_opts)
 --pp.printf("argv=%s; opts=%s, ending at %i, with optarg=%s",
 -- argv, opts, optind, optarg)
 local s2l = { } -- short to long option names conversion table
 for long, short in pairs(long_opts) do s2l[short]=long end
 local cfg = { chunks = { } }
 for i, short in pairs(opts) do
 local long = s2l[short]
 if chunk_options[long] then table.insert(cfg.chunks, { tag=long, optarg[i] })
 else cfg[long] = optarg[i] or true end
 end
 cfg.params = { select(optind, ...) }
 return cfg
end

function M.main (...)

 local cfg = M.cmdline_parser(...)

 -------------------------------------------------------------------
 -- Print messages if in verbose mode
 -------------------------------------------------------------------
 local function verb_print (fmt, ...)
 if cfg.verbose then
 return pp.printf ("[ "..fmt.." ]", ...)
 end
 end

 if cfg.verbose then
 verb_print("raw options: %s", cfg)
 end

 -------------------------------------------------------------------
 -- If there's no chunk but there are params, interpret the first
 -- param as a file name.
 if not next(cfg.chunks) and next(cfg.params) then
 local the_file = table.remove(cfg.params, 1)
 verb_print("Param %q considered as a source file", the_file)
 cfg.file={ the_file }
 end

 -------------------------------------------------------------------
 -- If nothing to do, run REPL loop
 if not next(cfg.chunks) and not cfg.interactive then
 verb_print "Nothing to compile nor run, force interactive loop"
 cfg.interactive=true
 end


 -------------------------------------------------------------------
 -- Run if asked to, or if no --output has been given
 -- if cfg.run==false it's been *forced* to false, don't override.
 if not cfg.run and not cfg.output then
 verb_print("No output file specified; I'll run the program")
 cfg.run = true
 end

 local code = { }

 -------------------------------------------------------------------
 -- Get ASTs from sources

 local last_file_idx
 for i, x in ipairs(cfg.chunks) do
 local compiler = mlc.new()
 local tag, val = x.tag, x[1]
 verb_print("Compiling %s", x)
 local st, ast
 if tag=='library' then
 ast = { tag='Call',
 {tag='Id', "require" },
 {tag='String', val } }
 elseif tag=='literal' then ast = compiler :src_to_ast(val)
 elseif tag=='file' then
 ast = compiler :srcfile_to_ast(val)
 -- Isolate each file in a separate fenv
 ast = { tag='Call',
 { tag='Function', { { tag='Dots'} }, ast },
 { tag='Dots' } }
 ast.source = '@'..val
 code.source = '@'..val
 last_file_idx = i
 else
 error ("Bad option "..tag)
 end
 local valid = true -- TODO: check AST's correctness
 if not valid then
 pp.printf ("Cannot compile %s:\n%s", x, ast or "no msg")
 os.exit (AST_COMPILE_ERROR_NUMBER)
 end
 ast.origin = x
 table.insert(code, ast)
 end
 -- The last file returns the whole chunk's result
 if last_file_idx then
 -- transform +{ (function(...) -{ast} end)(...) }
 -- into +{ return (function(...) -{ast} end)(...) }
 local prv_ast = code[last_file_idx]
 local new_ast = { tag='Return', prv_ast }
 new_ast.source, new_ast.origin, prv_ast.source, prv_ast.origin =
 prv_ast.source, prv_ast.origin, nil, nil
 code[last_file_idx] = new_ast
 end

 -- Further uses of compiler won't involve AST transformations:
 -- they can share the same instance.
 -- TODO: reuse last instance if possible.
 local compiler = mlc.new()

 -------------------------------------------------------------------
 -- AST printing
 if cfg['print-ast'] or cfg['print-ast-lineinfo'] then
 verb_print "Resulting AST:"
 for _, x in ipairs(code) do
 pp.printf("--- AST From %s: ---", x.source)
 if x.origin and x.origin.tag=='File' then x=x[1][1][2][1] end
 local pp_cfg = cfg['print-ast-lineinfo']
 and { line_max=1, fix_indent=1, metalua_tag=1 }
 or { line_max=1, metalua_tag=1, hide_hash=1 }
 pp.print(x, pp_cfg)
 end
 end

 -------------------------------------------------------------------
 -- Source printing
 if cfg['print-src'] then
 verb_print "Resulting sources:"
 for _, x in ipairs(code) do
 printf("--- Source From %s: ---", table.tostring(x.source, 'nohash'))
 if x.origin and x.origin.tag=='File' then x=x[1][1][2] end
 print (compiler :ast2string (x))
 end
 end

 -- TODO: canonize/check AST

 local bytecode = compiler :ast_to_bytecode (code)
 code = nil

 -------------------------------------------------------------------
 -- Insert #!... command
 if cfg.sharpbang then
 local shbang = cfg.sharpbang
 verb_print ("Adding sharp-bang directive %q", shbang)
 if not shbang :match'^#!' then shbang = '#!' .. shbang end
 if not shbang :match'\n$' then shbang = shbang .. '\n' end
 bytecode = shbang .. bytecode
 end

 -------------------------------------------------------------------
 -- Save to file
 if cfg.output then
 -- FIXME: handle '-'
 verb_print ("Saving to file %q", cfg.output)
 local file, err_msg = io.open(cfg.output, 'wb')
 if not file then error("can't open output file: "..err_msg) end
 file:write(bytecode)
 file:close()
 if cfg.sharpbang and os.getenv "OS" ~= "Windows_NT" then
 pcall(os.execute, 'chmod a+x "'..cfg.output..'"')
 end
 end

 -------------------------------------------------------------------
 -- Run compiled code
 if cfg.run then
 verb_print "Running"
 local f = compiler :bytecode_to_function (bytecode)
 bytecode = nil
 -- FIXME: isolate execution in a ring
 -- FIXME: check for failures
 local function print_traceback (errmsg)
 return errmsg .. '\n' .. debug.traceback ('',2) .. '\n'
 end
 local function g() return f(unpack (cfg.params)) end
 local st, msg = xpcall(g, print_traceback)
 if not st then
 io.stderr:write(msg)
 os.exit(RUNTIME_ERROR_NUMBER)
 end
 end

 -------------------------------------------------------------------
 -- Run REPL loop
 if cfg.interactive then
 verb_print "Starting REPL loop"
 require 'metalua.repl' .run()
 end

 verb_print "Done"

end

return M.main(...)