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Diffstat (limited to 'contrib/luasrcdiet/lua/lparser.lua')
| -rw-r--r-- | contrib/luasrcdiet/lua/lparser.lua | 1295 |
1 files changed, 1295 insertions, 0 deletions
diff --git a/contrib/luasrcdiet/lua/lparser.lua b/contrib/luasrcdiet/lua/lparser.lua new file mode 100644 index 000000000..a1e10e016 --- /dev/null +++ b/contrib/luasrcdiet/lua/lparser.lua @@ -0,0 +1,1295 @@ +--[[-------------------------------------------------------------------- + + lparser.lua: Lua 5.1 parser in Lua + This file is part of LuaSrcDiet, based on Yueliang material. + + Copyright (c) 2008 Kein-Hong Man <khman@users.sf.net> + The COPYRIGHT file describes the conditions + under which this software may be distributed. + + See the ChangeLog for more information. + +----------------------------------------------------------------------]] + +--[[-------------------------------------------------------------------- +-- NOTES: +-- * This is a version of the native 5.1.x parser from Yueliang 0.4.0, +-- with significant modifications to handle LuaSrcDiet's needs: +-- (1) needs pre-built token tables instead of a module.method +-- (2) lparser.error is an optional error handler (from llex) +-- (3) not full parsing, currently fakes raw/unlexed constants +-- (4) parser() returns globalinfo, localinfo tables +-- * Please read technotes.txt for more technical details. +-- * NO support for 'arg' vararg functions (LUA_COMPAT_VARARG) +-- * A lot of the parser is unused, but might later be useful for +-- full-on parsing and analysis for a few measly bytes saved. +----------------------------------------------------------------------]] + +local base = _G +local string = require "string" +module "lparser" +local _G = base.getfenv() + +--[[-------------------------------------------------------------------- +-- variable and data structure initialization +----------------------------------------------------------------------]] + +---------------------------------------------------------------------- +-- initialization: main variables +---------------------------------------------------------------------- + +local toklist, -- grammar-only token tables (token table, + seminfolist, -- semantic information table, line number + toklnlist, -- table, cross-reference table) + xreflist, + tpos, -- token position + + line, -- start line # for error messages + lastln, -- last line # for ambiguous syntax chk + tok, seminfo, ln, xref, -- token, semantic info, line + nameref, -- proper position of <name> token + fs, -- current function state + top_fs, -- top-level function state + + globalinfo, -- global variable information table + globallookup, -- global variable name lookup table + localinfo, -- local variable information table + ilocalinfo, -- inactive locals (prior to activation) + ilocalrefs -- corresponding references to activate + +-- forward references for local functions +local explist1, expr, block, exp1, body, chunk + +---------------------------------------------------------------------- +-- initialization: data structures +---------------------------------------------------------------------- + +local gmatch = string.gmatch + +local block_follow = {} -- lookahead check in chunk(), returnstat() +for v in gmatch("else elseif end until <eof>", "%S+") do + block_follow[v] = true +end + +local stat_call = {} -- lookup for calls in stat() +for v in gmatch("if while do for repeat function local return break", "%S+") do + stat_call[v] = v.."_stat" +end + +local binopr_left = {} -- binary operators, left priority +local binopr_right = {} -- binary operators, right priority +for op, lt, rt in gmatch([[ +{+ 6 6}{- 6 6}{* 7 7}{/ 7 7}{% 7 7} +{^ 10 9}{.. 5 4} +{~= 3 3}{== 3 3} +{< 3 3}{<= 3 3}{> 3 3}{>= 3 3} +{and 2 2}{or 1 1} +]], "{(%S+)%s(%d+)%s(%d+)}") do + binopr_left[op] = lt + 0 + binopr_right[op] = rt + 0 +end + +local unopr = { ["not"] = true, ["-"] = true, + ["#"] = true, } -- unary operators +local UNARY_PRIORITY = 8 -- priority for unary operators + +--[[-------------------------------------------------------------------- +-- support functions +----------------------------------------------------------------------]] + +---------------------------------------------------------------------- +-- formats error message and throws error (duplicated from llex) +-- * a simplified version, does not report what token was responsible +---------------------------------------------------------------------- + +local function errorline(s, line) + local e = error or base.error + e(string.format("(source):%d: %s", line or ln, s)) +end + +---------------------------------------------------------------------- +-- handles incoming token, semantic information pairs +-- * NOTE: 'nextt' is named 'next' originally +---------------------------------------------------------------------- + +-- reads in next token +local function nextt() + lastln = toklnlist[tpos] + tok, seminfo, ln, xref + = toklist[tpos], seminfolist[tpos], toklnlist[tpos], xreflist[tpos] + tpos = tpos + 1 +end + +-- peek at next token (single lookahead for table constructor) +local function lookahead() + return toklist[tpos] +end + +---------------------------------------------------------------------- +-- throws a syntax error, or if token expected is not there +---------------------------------------------------------------------- + +local function syntaxerror(msg) + local tok = tok + if tok ~= "<number>" and tok ~= "<string>" then + if tok == "<name>" then tok = seminfo end + tok = "'"..tok.."'" + end + errorline(msg.." near "..tok) +end + +local function error_expected(token) + syntaxerror("'"..token.."' expected") +end + +---------------------------------------------------------------------- +-- tests for a token, returns outcome +-- * return value changed to boolean +---------------------------------------------------------------------- + +local function testnext(c) + if tok == c then nextt(); return true end +end + +---------------------------------------------------------------------- +-- check for existence of a token, throws error if not found +---------------------------------------------------------------------- + +local function check(c) + if tok ~= c then error_expected(c) end +end + +---------------------------------------------------------------------- +-- verify existence of a token, then skip it +---------------------------------------------------------------------- + +local function checknext(c) + check(c); nextt() +end + +---------------------------------------------------------------------- +-- throws error if condition not matched +---------------------------------------------------------------------- + +local function check_condition(c, msg) + if not c then syntaxerror(msg) end +end + +---------------------------------------------------------------------- +-- verifies token conditions are met or else throw error +---------------------------------------------------------------------- + +local function check_match(what, who, where) + if not testnext(what) then + if where == ln then + error_expected(what) + else + syntaxerror("'"..what.."' expected (to close '"..who.."' at line "..where..")") + end + end +end + +---------------------------------------------------------------------- +-- expect that token is a name, return the name +---------------------------------------------------------------------- + +local function str_checkname() + check("<name>") + local ts = seminfo + nameref = xref + nextt() + return ts +end + +---------------------------------------------------------------------- +-- adds given string s in string pool, sets e as VK +---------------------------------------------------------------------- + +local function codestring(e, s) + e.k = "VK" +end + +---------------------------------------------------------------------- +-- consume a name token, adds it to string pool +---------------------------------------------------------------------- + +local function checkname(e) + codestring(e, str_checkname()) +end + +--[[-------------------------------------------------------------------- +-- variable (global|local|upvalue) handling +-- * to track locals and globals, we can extend Yueliang's minimal +-- variable management code with little trouble +-- * entry point is singlevar() for variable lookups +-- * lookup tables (bl.locallist) are maintained awkwardly in the basic +-- block data structures, PLUS the function data structure (this is +-- an inelegant hack, since bl is nil for the top level of a function) +----------------------------------------------------------------------]] + +---------------------------------------------------------------------- +-- register a local variable, create local variable object, set in +-- to-activate variable list +-- * used in new_localvarliteral(), parlist(), fornum(), forlist(), +-- localfunc(), localstat() +---------------------------------------------------------------------- + +local function new_localvar(name, special) + local bl = fs.bl + local locallist + -- locate locallist in current block object or function root object + if bl then + locallist = bl.locallist + else + locallist = fs.locallist + end + -- build local variable information object and set localinfo + local id = #localinfo + 1 + localinfo[id] = { -- new local variable object + name = name, -- local variable name + xref = { nameref }, -- xref, first value is declaration + decl = nameref, -- location of declaration, = xref[1] + } + if special then -- "self" must be not be changed + localinfo[id].isself = true + end + -- this can override a local with the same name in the same scope + -- but first, keep it inactive until it gets activated + local i = #ilocalinfo + 1 + ilocalinfo[i] = id + ilocalrefs[i] = locallist +end + +---------------------------------------------------------------------- +-- actually activate the variables so that they are visible +-- * remember Lua semantics, e.g. RHS is evaluated first, then LHS +-- * used in parlist(), forbody(), localfunc(), localstat(), body() +---------------------------------------------------------------------- + +local function adjustlocalvars(nvars) + local sz = #ilocalinfo + -- i goes from left to right, in order of local allocation, because + -- of something like: local a,a,a = 1,2,3 which gives a = 3 + while nvars > 0 do + nvars = nvars - 1 + local i = sz - nvars + local id = ilocalinfo[i] -- local's id + local obj = localinfo[id] + local name = obj.name -- name of local + obj.act = xref -- set activation location + ilocalinfo[i] = nil + local locallist = ilocalrefs[i] -- ref to lookup table to update + ilocalrefs[i] = nil + local existing = locallist[name] -- if existing, remove old first! + if existing then -- do not overlap, set special + obj = localinfo[existing] -- form of rem, as -id + obj.rem = -id + end + locallist[name] = id -- activate, now visible to Lua + end +end + +---------------------------------------------------------------------- +-- remove (deactivate) variables in current scope (before scope exits) +-- * zap entire locallist tables since we are not allocating registers +-- * used in leaveblock(), close_func() +---------------------------------------------------------------------- + +local function removevars() + local bl = fs.bl + local locallist + -- locate locallist in current block object or function root object + if bl then + locallist = bl.locallist + else + locallist = fs.locallist + end + -- enumerate the local list at current scope and deactivate 'em + for name, id in base.pairs(locallist) do + local obj = localinfo[id] + obj.rem = xref -- set deactivation location + end +end + +---------------------------------------------------------------------- +-- creates a new local variable given a name +-- * skips internal locals (those starting with '('), so internal +-- locals never needs a corresponding adjustlocalvars() call +-- * special is true for "self" which must not be optimized +-- * used in fornum(), forlist(), parlist(), body() +---------------------------------------------------------------------- + +local function new_localvarliteral(name, special) + if string.sub(name, 1, 1) == "(" then -- can skip internal locals + return + end + new_localvar(name, special) +end + +---------------------------------------------------------------------- +-- search the local variable namespace of the given fs for a match +-- * returns localinfo index +-- * used only in singlevaraux() +---------------------------------------------------------------------- + +local function searchvar(fs, n) + local bl = fs.bl + local locallist + if bl then + locallist = bl.locallist + while locallist do + if locallist[n] then return locallist[n] end -- found + bl = bl.prev + locallist = bl and bl.locallist + end + end + locallist = fs.locallist + return locallist[n] or -1 -- found or not found (-1) +end + +---------------------------------------------------------------------- +-- handle locals, globals and upvalues and related processing +-- * search mechanism is recursive, calls itself to search parents +-- * used only in singlevar() +---------------------------------------------------------------------- + +local function singlevaraux(fs, n, var) + if fs == nil then -- no more levels? + var.k = "VGLOBAL" -- default is global variable + return "VGLOBAL" + else + local v = searchvar(fs, n) -- look up at current level + if v >= 0 then + var.k = "VLOCAL" + var.id = v + -- codegen may need to deal with upvalue here + return "VLOCAL" + else -- not found at current level; try upper one + if singlevaraux(fs.prev, n, var) == "VGLOBAL" then + return "VGLOBAL" + end + -- else was LOCAL or UPVAL, handle here + var.k = "VUPVAL" -- upvalue in this level + return "VUPVAL" + end--if v + end--if fs +end + +---------------------------------------------------------------------- +-- consume a name token, creates a variable (global|local|upvalue) +-- * used in prefixexp(), funcname() +---------------------------------------------------------------------- + +local function singlevar(v) + local name = str_checkname() + singlevaraux(fs, name, v) + ------------------------------------------------------------------ + -- variable tracking + ------------------------------------------------------------------ + if v.k == "VGLOBAL" then + -- if global being accessed, keep track of it by creating an object + local id = globallookup[name] + if not id then + id = #globalinfo + 1 + globalinfo[id] = { -- new global variable object + name = name, -- global variable name + xref = { nameref }, -- xref, first value is declaration + } + globallookup[name] = id -- remember it + else + local obj = globalinfo[id].xref + obj[#obj + 1] = nameref -- add xref + end + else + -- local/upvalue is being accessed, keep track of it + local id = v.id + local obj = localinfo[id].xref + obj[#obj + 1] = nameref -- add xref + end +end + +--[[-------------------------------------------------------------------- +-- state management functions with open/close pairs +----------------------------------------------------------------------]] + +---------------------------------------------------------------------- +-- enters a code unit, initializes elements +---------------------------------------------------------------------- + +local function enterblock(isbreakable) + local bl = {} -- per-block state + bl.isbreakable = isbreakable + bl.prev = fs.bl + bl.locallist = {} + fs.bl = bl +end + +---------------------------------------------------------------------- +-- leaves a code unit, close any upvalues +---------------------------------------------------------------------- + +local function leaveblock() + local bl = fs.bl + removevars() + fs.bl = bl.prev +end + +---------------------------------------------------------------------- +-- opening of a function +-- * top_fs is only for anchoring the top fs, so that parser() can +-- return it to the caller function along with useful output +-- * used in parser() and body() +---------------------------------------------------------------------- + +local function open_func() + local new_fs -- per-function state + if not fs then -- top_fs is created early + new_fs = top_fs + else + new_fs = {} + end + new_fs.prev = fs -- linked list of function states + new_fs.bl = nil + new_fs.locallist = {} + fs = new_fs +end + +---------------------------------------------------------------------- +-- closing of a function +-- * used in parser() and body() +---------------------------------------------------------------------- + +local function close_func() + removevars() + fs = fs.prev +end + +--[[-------------------------------------------------------------------- +-- other parsing functions +-- * for table constructor, parameter list, argument list +----------------------------------------------------------------------]] + +---------------------------------------------------------------------- +-- parse a function name suffix, for function call specifications +-- * used in primaryexp(), funcname() +---------------------------------------------------------------------- + +local function field(v) + -- field -> ['.' | ':'] NAME + local key = {} + nextt() -- skip the dot or colon + checkname(key) + v.k = "VINDEXED" +end + +---------------------------------------------------------------------- +-- parse a table indexing suffix, for constructors, expressions +-- * used in recfield(), primaryexp() +---------------------------------------------------------------------- + +local function yindex(v) + -- index -> '[' expr ']' + nextt() -- skip the '[' + expr(v) + checknext("]") +end + +---------------------------------------------------------------------- +-- parse a table record (hash) field +-- * used in constructor() +---------------------------------------------------------------------- + +local function recfield(cc) + -- recfield -> (NAME | '['exp1']') = exp1 + local key, val = {}, {} + if tok == "<name>" then + checkname(key) + else-- tok == '[' + yindex(key) + end + checknext("=") + expr(val) +end + +---------------------------------------------------------------------- +-- emit a set list instruction if enough elements (LFIELDS_PER_FLUSH) +-- * note: retained in this skeleton because it modifies cc.v.k +-- * used in constructor() +---------------------------------------------------------------------- + +local function closelistfield(cc) + if cc.v.k == "VVOID" then return end -- there is no list item + cc.v.k = "VVOID" +end + +---------------------------------------------------------------------- +-- parse a table list (array) field +-- * used in constructor() +---------------------------------------------------------------------- + +local function listfield(cc) + expr(cc.v) +end + +---------------------------------------------------------------------- +-- parse a table constructor +-- * used in funcargs(), simpleexp() +---------------------------------------------------------------------- + +local function constructor(t) + -- constructor -> '{' [ field { fieldsep field } [ fieldsep ] ] '}' + -- field -> recfield | listfield + -- fieldsep -> ',' | ';' + local line = ln + local cc = {} + cc.v = {} + cc.t = t + t.k = "VRELOCABLE" + cc.v.k = "VVOID" + checknext("{") + repeat + if tok == "}" then break end + -- closelistfield(cc) here + local c = tok + if c == "<name>" then -- may be listfields or recfields + if lookahead() ~= "=" then -- look ahead: expression? + listfield(cc) + else + recfield(cc) + end + elseif c == "[" then -- constructor_item -> recfield + recfield(cc) + else -- constructor_part -> listfield + listfield(cc) + end + until not testnext(",") and not testnext(";") + check_match("}", "{", line) + -- lastlistfield(cc) here +end + +---------------------------------------------------------------------- +-- parse the arguments (parameters) of a function declaration +-- * used in body() +---------------------------------------------------------------------- + +local function parlist() + -- parlist -> [ param { ',' param } ] + local nparams = 0 + if tok ~= ")" then -- is 'parlist' not empty? + repeat + local c = tok + if c == "<name>" then -- param -> NAME + new_localvar(str_checkname()) + nparams = nparams + 1 + elseif c == "..." then + nextt() + fs.is_vararg = true + else + syntaxerror("<name> or '...' expected") + end + until fs.is_vararg or not testnext(",") + end--if + adjustlocalvars(nparams) +end + +---------------------------------------------------------------------- +-- parse the parameters of a function call +-- * contrast with parlist(), used in function declarations +-- * used in primaryexp() +---------------------------------------------------------------------- + +local function funcargs(f) + local args = {} + local line = ln + local c = tok + if c == "(" then -- funcargs -> '(' [ explist1 ] ')' + if line ~= lastln then + syntaxerror("ambiguous syntax (function call x new statement)") + end + nextt() + if tok == ")" then -- arg list is empty? + args.k = "VVOID" + else + explist1(args) + end + check_match(")", "(", line) + elseif c == "{" then -- funcargs -> constructor + constructor(args) + elseif c == "<string>" then -- funcargs -> STRING + codestring(args, seminfo) + nextt() -- must use 'seminfo' before 'next' + else + syntaxerror("function arguments expected") + return + end--if c + f.k = "VCALL" +end + +--[[-------------------------------------------------------------------- +-- mostly expression functions +----------------------------------------------------------------------]] + +---------------------------------------------------------------------- +-- parses an expression in parentheses or a single variable +-- * used in primaryexp() +---------------------------------------------------------------------- + +local function prefixexp(v) + -- prefixexp -> NAME | '(' expr ')' + local c = tok + if c == "(" then + local line = ln + nextt() + expr(v) + check_match(")", "(", line) + elseif c == "<name>" then + singlevar(v) + else + syntaxerror("unexpected symbol") + end--if c +end + +---------------------------------------------------------------------- +-- parses a prefixexp (an expression in parentheses or a single +-- variable) or a function call specification +-- * used in simpleexp(), assignment(), expr_stat() +---------------------------------------------------------------------- + +local function primaryexp(v) + -- primaryexp -> + -- prefixexp { '.' NAME | '[' exp ']' | ':' NAME funcargs | funcargs } + prefixexp(v) + while true do + local c = tok + if c == "." then -- field + field(v) + elseif c == "[" then -- '[' exp1 ']' + local key = {} + yindex(key) + elseif c == ":" then -- ':' NAME funcargs + local key = {} + nextt() + checkname(key) + funcargs(v) + elseif c == "(" or c == "<string>" or c == "{" then -- funcargs + funcargs(v) + else + return + end--if c + end--while +end + +---------------------------------------------------------------------- +-- parses general expression types, constants handled here +-- * used in subexpr() +---------------------------------------------------------------------- + +local function simpleexp(v) + -- simpleexp -> NUMBER | STRING | NIL | TRUE | FALSE | ... | + -- constructor | FUNCTION body | primaryexp + local c = tok + if c == "<number>" then + v.k = "VKNUM" + elseif c == "<string>" then + codestring(v, seminfo) + elseif c == "nil" then + v.k = "VNIL" + elseif c == "true" then + v.k = "VTRUE" + elseif c == "false" then + v.k = "VFALSE" + elseif c == "..." then -- vararg + check_condition(fs.is_vararg == true, + "cannot use '...' outside a vararg function"); + v.k = "VVARARG" + elseif c == "{" then -- constructor + constructor(v) + return + elseif c == "function" then + nextt() + body(v, false, ln) + return + else + primaryexp(v) + return + end--if c + nextt() +end + +------------------------------------------------------------------------ +-- Parse subexpressions. Includes handling of unary operators and binary +-- operators. A subexpr is given the rhs priority level of the operator +-- immediately left of it, if any (limit is -1 if none,) and if a binop +-- is found, limit is compared with the lhs priority level of the binop +-- in order to determine which executes first. +-- * recursively called +-- * used in expr() +------------------------------------------------------------------------ + +local function subexpr(v, limit) + -- subexpr -> (simpleexp | unop subexpr) { binop subexpr } + -- * where 'binop' is any binary operator with a priority + -- higher than 'limit' + local op = tok + local uop = unopr[op] + if uop then + nextt() + subexpr(v, UNARY_PRIORITY) + else + simpleexp(v) + end + -- expand while operators have priorities higher than 'limit' + op = tok + local binop = binopr_left[op] + while binop and binop > limit do + local v2 = {} + nextt() + -- read sub-expression with higher priority + local nextop = subexpr(v2, binopr_right[op]) + op = nextop + binop = binopr_left[op] + end + return op -- return first untreated operator +end + +---------------------------------------------------------------------- +-- Expression parsing starts here. Function subexpr is entered with the +-- left operator (which is non-existent) priority of -1, which is lower +-- than all actual operators. Expr information is returned in parm v. +-- * used in cond(), explist1(), index(), recfield(), listfield(), +-- prefixexp(), while_stat(), exp1() +---------------------------------------------------------------------- + +-- this is a forward-referenced local +function expr(v) + -- expr -> subexpr + subexpr(v, 0) +end + +--[[-------------------------------------------------------------------- +-- third level parsing functions +----------------------------------------------------------------------]] + +------------------------------------------------------------------------ +-- parse a variable assignment sequence +-- * recursively called +-- * used in expr_stat() +------------------------------------------------------------------------ + +local function assignment(v) + local e = {} + local c = v.v.k + check_condition(c == "VLOCAL" or c == "VUPVAL" or c == "VGLOBAL" + or c == "VINDEXED", "syntax error") + if testnext(",") then -- assignment -> ',' primaryexp assignment + local nv = {} -- expdesc + nv.v = {} + primaryexp(nv.v) + -- lparser.c deals with some register usage conflict here + assignment(nv) + else -- assignment -> '=' explist1 + checknext("=") + explist1(e) + return -- avoid default + end + e.k = "VNONRELOC" +end + +---------------------------------------------------------------------- +-- parse a for loop body for both versions of the for loop +-- * used in fornum(), forlist() +---------------------------------------------------------------------- + +local function forbody(nvars, isnum) + -- forbody -> DO block + checknext("do") + enterblock(false) -- scope for declared variables + adjustlocalvars(nvars) + block() + leaveblock() -- end of scope for declared variables +end + +---------------------------------------------------------------------- +-- parse a numerical for loop, calls forbody() +-- * used in for_stat() +---------------------------------------------------------------------- + +local function fornum(varname) + -- fornum -> NAME = exp1, exp1 [, exp1] DO body + local line = line + new_localvarliteral("(for index)") + new_localvarliteral("(for limit)") + new_localvarliteral("(for step)") + new_localvar(varname) + checknext("=") + exp1() -- initial value + checknext(",") + exp1() -- limit + if testnext(",") then + exp1() -- optional step + else + -- default step = 1 + end + forbody(1, true) +end + +---------------------------------------------------------------------- +-- parse a generic for loop, calls forbody() +-- * used in for_stat() +---------------------------------------------------------------------- + +local function forlist(indexname) + -- forlist -> NAME {, NAME} IN explist1 DO body + local e = {} + -- create control variables + new_localvarliteral("(for generator)") + new_localvarliteral("(for state)") + new_localvarliteral("(for control)") + -- create declared variables + new_localvar(indexname) + local nvars = 1 + while testnext(",") do + new_localvar(str_checkname()) + nvars = nvars + 1 + end + checknext("in") + local line = line + explist1(e) + forbody(nvars, false) +end + +---------------------------------------------------------------------- +-- parse a function name specification +-- * used in func_stat() +---------------------------------------------------------------------- + +local function funcname(v) + -- funcname -> NAME {field} [':' NAME] + local needself = false + singlevar(v) + while tok == "." do + field(v) + end + if tok == ":" then + needself = true + field(v) + end + return needself +end + +---------------------------------------------------------------------- +-- parse the single expressions needed in numerical for loops +-- * used in fornum() +---------------------------------------------------------------------- + +-- this is a forward-referenced local +function exp1() + -- exp1 -> expr + local e = {} + expr(e) +end + +---------------------------------------------------------------------- +-- parse condition in a repeat statement or an if control structure +-- * used in repeat_stat(), test_then_block() +---------------------------------------------------------------------- + +local function cond() + -- cond -> expr + local v = {} + expr(v) -- read condition +end + +---------------------------------------------------------------------- +-- parse part of an if control structure, including the condition +-- * used in if_stat() +---------------------------------------------------------------------- + +local function test_then_block() + -- test_then_block -> [IF | ELSEIF] cond THEN block + nextt() -- skip IF or ELSEIF + cond() + checknext("then") + block() -- 'then' part +end + +---------------------------------------------------------------------- +-- parse a local function statement +-- * used in local_stat() +---------------------------------------------------------------------- + +local function localfunc() + -- localfunc -> NAME body + local v, b = {} + new_localvar(str_checkname()) + v.k = "VLOCAL" + adjustlocalvars(1) + body(b, false, ln) +end + +---------------------------------------------------------------------- +-- parse a local variable declaration statement +-- * used in local_stat() +---------------------------------------------------------------------- + +local function localstat() + -- localstat -> NAME {',' NAME} ['=' explist1] + local nvars = 0 + local e = {} + repeat + new_localvar(str_checkname()) + nvars = nvars + 1 + until not testnext(",") + if testnext("=") then + explist1(e) + else + e.k = "VVOID" + end + adjustlocalvars(nvars) +end + +---------------------------------------------------------------------- +-- parse a list of comma-separated expressions +-- * used in return_stat(), localstat(), funcargs(), assignment(), +-- forlist() +---------------------------------------------------------------------- + +-- this is a forward-referenced local +function explist1(e) + -- explist1 -> expr { ',' expr } + expr(e) + while testnext(",") do + expr(e) + end +end + +---------------------------------------------------------------------- +-- parse function declaration body +-- * used in simpleexp(), localfunc(), func_stat() +---------------------------------------------------------------------- + +-- this is a forward-referenced local +function body(e, needself, line) + -- body -> '(' parlist ')' chunk END + open_func() + checknext("(") + if needself then + new_localvarliteral("self", true) + adjustlocalvars(1) + end + parlist() + checknext(")") + chunk() + check_match("end", "function", line) + close_func() +end + +---------------------------------------------------------------------- +-- parse a code block or unit +-- * used in do_stat(), while_stat(), forbody(), test_then_block(), +-- if_stat() +---------------------------------------------------------------------- + +-- this is a forward-referenced local +function block() + -- block -> chunk + enterblock(false) + chunk() + leaveblock() +end + +--[[-------------------------------------------------------------------- +-- second level parsing functions, all with '_stat' suffix +-- * since they are called via a table lookup, they cannot be local +-- functions (a lookup table of local functions might be smaller...) +-- * stat() -> *_stat() +----------------------------------------------------------------------]] + +---------------------------------------------------------------------- +-- initial parsing for a for loop, calls fornum() or forlist() +-- * removed 'line' parameter (used to set debug information only) +-- * used in stat() +---------------------------------------------------------------------- + +function for_stat() + -- stat -> for_stat -> FOR (fornum | forlist) END + local line = line + enterblock(true) -- scope for loop and control variables + nextt() -- skip 'for' + local varname = str_checkname() -- first variable name + local c = tok + if c == "=" then + fornum(varname) + elseif c == "," or c == "in" then + forlist(varname) + else + syntaxerror("'=' or 'in' expected") + end + check_match("end", "for", line) + leaveblock() -- loop scope (`break' jumps to this point) +end + +---------------------------------------------------------------------- +-- parse a while-do control structure, body processed by block() +-- * used in stat() +---------------------------------------------------------------------- + +function while_stat() + -- stat -> while_stat -> WHILE cond DO block END + local line = line + nextt() -- skip WHILE + cond() -- parse condition + enterblock(true) + checknext("do") + block() + check_match("end", "while", line) + leaveblock() +end + +---------------------------------------------------------------------- +-- parse a repeat-until control structure, body parsed by chunk() +-- * originally, repeatstat() calls breakstat() too if there is an +-- upvalue in the scope block; nothing is actually lexed, it is +-- actually the common code in breakstat() for closing of upvalues +-- * used in stat() +---------------------------------------------------------------------- + +function repeat_stat() + -- stat -> repeat_stat -> REPEAT block UNTIL cond + local line = line + enterblock(true) -- loop block + enterblock(false) -- scope block + nextt() -- skip REPEAT + chunk() + check_match("until", "repeat", line) + cond() + -- close upvalues at scope level below + leaveblock() -- finish scope + leaveblock() -- finish loop +end + +---------------------------------------------------------------------- +-- parse an if control structure +-- * used in stat() +---------------------------------------------------------------------- + +function if_stat() + -- stat -> if_stat -> IF cond THEN block + -- {ELSEIF cond THEN block} [ELSE block] END + local line = line + local v = {} + test_then_block() -- IF cond THEN block + while tok == "elseif" do + test_then_block() -- ELSEIF cond THEN block + end + if tok == "else" then + nextt() -- skip ELSE + block() -- 'else' part + end + check_match("end", "if", line) +end + +---------------------------------------------------------------------- +-- parse a return statement +-- * used in stat() +---------------------------------------------------------------------- + +function return_stat() + -- stat -> return_stat -> RETURN explist + local e = {} + nextt() -- skip RETURN + local c = tok + if block_follow[c] or c == ";" then + -- return no values + else + explist1(e) -- optional return values + end +end + +---------------------------------------------------------------------- +-- parse a break statement +-- * used in stat() +---------------------------------------------------------------------- + +function break_stat() + -- stat -> break_stat -> BREAK + local bl = fs.bl + nextt() -- skip BREAK + while bl and not bl.isbreakable do -- find a breakable block + bl = bl.prev + end + if not bl then + syntaxerror("no loop to break") + end +end + +---------------------------------------------------------------------- +-- parse a function call with no returns or an assignment statement +-- * the struct with .prev is used for name searching in lparse.c, +-- so it is retained for now; present in assignment() also +-- * used in stat() +---------------------------------------------------------------------- + +function expr_stat() + -- stat -> expr_stat -> func | assignment + local v = {} + v.v = {} + primaryexp(v.v) + if v.v.k == "VCALL" then -- stat -> func + -- call statement uses no results + else -- stat -> assignment + v.prev = nil + assignment(v) + end +end + +---------------------------------------------------------------------- +-- parse a function statement +-- * used in stat() +---------------------------------------------------------------------- + +function function_stat() + -- stat -> function_stat -> FUNCTION funcname body + local line = line + local v, b = {}, {} + nextt() -- skip FUNCTION + local needself = funcname(v) + body(b, needself, line) +end + +---------------------------------------------------------------------- +-- parse a simple block enclosed by a DO..END pair +-- * used in stat() +---------------------------------------------------------------------- + +function do_stat() + -- stat -> do_stat -> DO block END + local line = line + nextt() -- skip DO + block() + check_match("end", "do", line) +end + +---------------------------------------------------------------------- +-- parse a statement starting with LOCAL +-- * used in stat() +---------------------------------------------------------------------- + +function local_stat() + -- stat -> local_stat -> LOCAL FUNCTION localfunc + -- -> LOCAL localstat + nextt() -- skip LOCAL + if testnext("function") then -- local function? + localfunc() + else + localstat() + end +end + +--[[-------------------------------------------------------------------- +-- main functions, top level parsing functions +-- * accessible functions are: init(lexer), parser() +-- * [entry] -> parser() -> chunk() -> stat() +----------------------------------------------------------------------]] + +---------------------------------------------------------------------- +-- initial parsing for statements, calls '_stat' suffixed functions +-- * used in chunk() +---------------------------------------------------------------------- + +local function stat() + -- stat -> if_stat while_stat do_stat for_stat repeat_stat + -- function_stat local_stat return_stat break_stat + -- expr_stat + line = ln -- may be needed for error messages + local c = tok + local fn = stat_call[c] + -- handles: if while do for repeat function local return break + if fn then + _G[fn]() + -- return or break must be last statement + if c == "return" or c == "break" then return true end + else + expr_stat() + end + return false +end + +---------------------------------------------------------------------- +-- parse a chunk, which consists of a bunch of statements +-- * used in parser(), body(), block(), repeat_stat() +---------------------------------------------------------------------- + +-- this is a forward-referenced local +function chunk() + -- chunk -> { stat [';'] } + local islast = false + while not islast and not block_follow[tok] do + islast = stat() + testnext(";") + end +end + +---------------------------------------------------------------------- +-- performs parsing, returns parsed data structure +---------------------------------------------------------------------- + +function parser() + open_func() + fs.is_vararg = true -- main func. is always vararg + nextt() -- read first token + chunk() + check("<eof>") + close_func() + return globalinfo, localinfo +end + +---------------------------------------------------------------------- +-- initialization function +---------------------------------------------------------------------- + +function init(tokorig, seminfoorig, toklnorig) + tpos = 1 -- token position + top_fs = {} -- reset top level function state + ------------------------------------------------------------------ + -- set up grammar-only token tables; impedance-matching... + -- note that constants returned by the lexer is source-level, so + -- for now, fake(!) constant tokens (TK_NUMBER|TK_STRING|TK_LSTRING) + ------------------------------------------------------------------ + local j = 1 + toklist, seminfolist, toklnlist, xreflist = {}, {}, {}, {} + for i = 1, #tokorig do + local tok = tokorig[i] + local yep = true + if tok == "TK_KEYWORD" or tok == "TK_OP" then + tok = seminfoorig[i] + elseif tok == "TK_NAME" then + tok = "<name>" + seminfolist[j] = seminfoorig[i] + elseif tok == "TK_NUMBER" then + tok = "<number>" + seminfolist[j] = 0 -- fake! + elseif tok == "TK_STRING" or tok == "TK_LSTRING" then + tok = "<string>" + seminfolist[j] = "" -- fake! + elseif tok == "TK_EOS" then + tok = "<eof>" + else + -- non-grammar tokens; ignore them + yep = false + end + if yep then -- set rest of the information + toklist[j] = tok + toklnlist[j] = toklnorig[i] + xreflist[j] = i + j = j + 1 + end + end--for + ------------------------------------------------------------------ + -- initialize data structures for variable tracking + ------------------------------------------------------------------ + globalinfo, globallookup, localinfo = {}, {}, {} + ilocalinfo, ilocalrefs = {}, {} +end + +return _G |