---------------------------------------------------------------------- -- Metalua: $Id$ -- -- Summary: metalua parser, expression parser. This is part of the -- definition of module [mlp]. -- ---------------------------------------------------------------------- -- -- Copyright (c) 2006-2007, Fabien Fleutot <metalua@gmail.com>. -- -- This software is released under the MIT Licence, see licence.txt -- for details. -- ---------------------------------------------------------------------- -------------------------------------------------------------------------------- -- -- Exported API: -- * [mlp.expr()] -- * [mlp.expr_list()] -- * [mlp.func_val()] -- -------------------------------------------------------------------------------- --require "gg" --require "mlp_misc" --require "mlp_table" --require "mlp_meta" -------------------------------------------------------------------------------- -- These function wrappers (eta-expansions ctually) are just here to break -- some circular dependencies between mlp_xxx.lua files. -------------------------------------------------------------------------------- local function _expr (lx) return mlp.expr (lx) end local function _table_content (lx) return mlp.table_content (lx) end local function block (lx) return mlp.block (lx) end local function stat (lx) return mlp.stat (lx) end module ("mlp", package.seeall) -------------------------------------------------------------------------------- -- Non-empty expression list. Actually, this isn't used here, but that's -- handy to give to users. -------------------------------------------------------------------------------- expr_list = gg.list{ _expr, separators = "," } -------------------------------------------------------------------------------- -- Helpers for function applications / method applications -------------------------------------------------------------------------------- local func_args_content = gg.list { name = "function arguments", _expr, separators = ",", terminators = ")" } -- Used to parse methods local method_args = gg.multisequence{ name = "function argument(s)", { "{", table_content, "}" }, { "(", func_args_content, ")", builder = fget(1) }, default = function(lx) local r = opt_string(lx); return r and {r} or { } end } -------------------------------------------------------------------------------- -- [func_val] parses a function, from opening parameters parenthese to -- "end" keyword included. Used for anonymous functions as well as -- function declaration statements (both local and global). -- -- It's wrapped in a [_func_val] eta expansion, so that when expr -- parser uses the latter, they will notice updates of [func_val] -- definitions. -------------------------------------------------------------------------------- func_params_content = gg.list{ name="function parameters", gg.multisequence{ { "...", builder = "Dots" }, default = id }, separators = ",", terminators = {")", "|"} } local _func_params_content = function (lx) return func_params_content(lx) end func_val = gg.sequence { name="function body", "(", func_params_content, ")", block, "end", builder = "Function" } local _func_val = function (lx) return func_val(lx) end -------------------------------------------------------------------------------- -- Default parser for primary expressions -------------------------------------------------------------------------------- local function id_or_literal (lx) local a = lx:next() if a.tag~="Id" and a.tag~="String" and a.tag~="Number" then gg.parse_error (lx, "Unexpected expr token %s", _G.table.tostring(a)) end return a end -------------------------------------------------------------------------------- -- Builder generators for operators. Wouldn't be worth it if "|x|" notation -- were allowed, but then lua 5.1 wouldn't compile it -------------------------------------------------------------------------------- -- opf1 = |op_tag| |op, a| `Op{ {tag=op_tag}, a } local function opf1 (op_tag) return function (op, a) return {tag="Op", {tag=op_tag}, a } end end -- opf2 = |op_tag| |a, op, b| `Op{ {tag=op_tag}, a, b } local function opf2 (op_tag) return function (a, op, b) return {tag="Op", {tag=op_tag}, a, b } end end -------------------------------------------------------------------------------- -- -- complete expression -- -------------------------------------------------------------------------------- -- FIXME: set line number. In [expr] transformers probably expr = gg.expr { name = "expression", primary = gg.multisequence{ name="expr primary", { "(", _expr, ")", builder = "One" }, { "function", _func_val, builder = fget(1) }, { "-{", splice_content, "}", builder = fget(1) }, { "+{", quote_content, "}", builder = fget(1) }, { "nil", builder = "Nil" }, { "true", builder = "True" }, { "false", builder = "False" }, { "...", builder = "Dots" }, table, default = id_or_literal }, infix = { name="expr infix op", { "+", prec = 60, builder = opf2 "Add" }, { "-", prec = 60, builder = opf2 "Sub" }, { "*", prec = 70, builder = opf2 "Mul" }, { "/", prec = 70, builder = opf2 "Div" }, { "%", prec = 70, builder = opf2 "Mod" }, { "^", prec = 90, builder = opf2 "Pow", assoc = "right" }, { "..", prec = 40, builder = opf2 "Concat", assoc = "right" }, { "==", prec = 30, builder = opf2 "Eq" }, { "~=", prec = 30, builder = opf2 "Ne" }, { ">", prec = 30, builder = opf2 "Gt" }, { ">=", prec = 30, builder = opf2 "Ge" }, { "<", prec = 30, builder = opf2 "Lt" }, { "<=", prec = 30, builder = opf2 "Le" }, { "and",prec = 20, builder = opf2 "And" }, { "or", prec = 10, builder = opf2 "Or" } }, prefix = { name="expr prefix op", { "not",prec = 80, builder = opf1 "Not" }, { "#", prec = 80, builder = opf1 "Len" }, { "-", prec = 80, builder = opf1 "Sub" } }, suffix = { name="expr suffix op", { "[", _expr, "]", builder = function (tab, idx) return {tag="Index", tab, idx[1]} end}, { ".", id, builder = function (tab, field) return {tag="Index", tab, id2string(field[1])} end }, { "(", func_args_content, ")", builder = function(f, args) return {tag="Call", f, unpack(args[1])} end }, { "{", _table_content, "}", builder = function (f, arg) return {tag="Call", f, arg[1]} end}, { ":", id, method_args, builder = function (obj, post) return {tag="Method", obj, id2string(post[1]), unpack(post[2])} end}, { "+{", quote_content, "}", builder = function (f, arg) return {tag="Call", f, arg[1] } end }, default = { parse=mlp.opt_string, builder = function(f, arg) return {tag="Call", f, arg } end } } }