diff options
Diffstat (limited to 'src/lparser.js')
| -rw-r--r-- | src/lparser.js | 476 |
1 files changed, 465 insertions, 11 deletions
diff --git a/src/lparser.js b/src/lparser.js index 8f3a48d..807e8e7 100644 --- a/src/lparser.js +++ b/src/lparser.js @@ -3,17 +3,22 @@ const assert = require('assert'); -const lua = require('./lua.js'); -const llex = require('./llex.js'); -const lfunc = require('./lfunc.js'); -const lobject = require('./lobject.js'); -const lcode = require('./lcode.js'); -const R = llex.RESERVED; -const TValue = lobject.TValue; -const CT = lua.constants_type; -const Table = lobject.Table; -const Proto = lfunc.Proto; -const UpVal = lfunc.UpVal; +const lcode = require('./lcode.js'); +const lfunc = require('./lfunc.js'); +const llex = require('./llex.js'); +const llimit = require('./llimit.js'); +const lobject = require('./lobject.js'); +const lopcode = require('./lopcode.js'); +const lua = require('./lua.js'); +const BinOpr = lcode.BinOpr; +const CT = lua.constants_type; +const OpCodesI = lopcode.OpCodesI; +const Proto = lfunc.Proto; +const R = llex.RESERVED; +const TValue = lobject.TValue; +const Table = lobject.Table; +const UnOpr = lcode.UnOpr; +const UpVal = lfunc.UpVal; class BlockCnt { constructor() { @@ -109,17 +114,61 @@ const checklimit = function(fs, v, l, what) { if (v > l) errorlimit(fs, l, what); }; +const testnext = function(ls, c) { + if (ls.t.token === c) { + llex.luaX_next(ls); + return true; + } + + return false; +}; + const check = function(ls, c) { if (ls.t.token !== c) error_expected(ls, c); }; +const checknext = function(ls, c) { + check(ls, c); + llex.luaX_next(ls); +}; + +const check_condition = function(ls, c, msg) { + if (!c) + llex.luaX_syntaxerror(ls, msg); +}; + +const check_match = function(ls, what, who, where) { + if (!testnext(ls, what)) { + if (where === ls.linenumber) + error_expected(ls, what); + else + llex.luaX_syntaxerror(ls, + `${llex.luaX_token2str(ls, what)} expected (to close ${llex.luaX_token2str(ls, who)} at line ${where}`); + } +}; + +const str_checkname = function(ls) { + check(ls, R.TK_NAME); + let ts = ls.t.seminfo.ts; + llex.luaX_next(ls); + return ts; +}; + const init_exp = function(e, k, i) { e.f = e.t = lcode.NO_JUMP; e.k = k; e.u.info = i; }; +const codestring = function(ls, e, s) { + init_exp(e, expkind.VK, lcode.luaK_stringK(ls.fs, s)); +}; + +const checkname = function(ls, e) { + codestring(ls, e, str_checkname(ls)); +}; + const getlocvar = function(fs, i) { let idx = fs.ls.dyd.actvar.arr[fs.firstlocal + i].idx; assert(idx < fs.nlocvars); @@ -142,6 +191,16 @@ const newupvalue = function(fs, name, v) { return fs.nups++; }; +const enterlevel = function(ls) { + let L = ls.L; + ++L.nCcalls; + checklimit(ls.fs, L.nCcalls, llimit.LUAI_MAXCCALLS, "JS levels"); +}; + +const leavelevel = function(ls) { + return ls.L.nCcalls--; +}; + const closegoto = function(ls, g, label) { let fs = ls.fs; let gl = ls.dyd.gt; @@ -313,6 +372,401 @@ const close_func = function(ls) { ls.fs = fs.prev; }; +/*============================================================*/ +/* GRAMMAR RULES */ +/*============================================================*/ + +const statlist = function(ls) { + /* statlist -> { stat [';'] } */ + while (!block_follow(ls, 1)) { + if (ls.t.token === R.TK_RETURN) { + statement(ls); + return; /* 'return' must be last statement */ + } + statement(ls); + } +}; + +const yindex = function(ls, v) { + /* index -> '[' expr ']' */ + llex.luaX_next(ls); /* skip the '[' */ + expr(ls, v); + lcode.luaK_exp2val(ls.fs, v); + checknext(ls, ']'); +}; + +/* +** {====================================================================== +** Rules for Constructors +** ======================================================================= +*/ + +class ConsControl { + constructor() { + this.v = new expdesc(); /* last list item read */ + this.t = new expdesc(); /* table descriptor */ + this.nh = NaN; /* total number of 'record' elements */ + this.na = NaN; /* total number of array elements */ + this.tostore = NaN; /* number of array elements pending to be stored */ + } +} + +const recfield = function(ls, cc) { + /* recfield -> (NAME | '['exp1']') = exp1 */ + let fs = ls.fs; + let reg = ls.fs.freereg; + let key = new expdesc(); + let val = new expdesc(); + + if (ls.t.token === R.TK_NAME) { + checklimit(fs, cc.nh, Number.MAX_SAFE_INTEGER, "items in a constructor"); + checkname(ls, key); + } else /* ls->t.token == '[' */ + yindex(ls, key); + cc.nh++; + checknext(ls, '='); + let rkkey = lcode.luaK_exp2RK(fs, key); + expr(ls, val); + lcode.luaK_codeABC(fs, OpCodesI.OP_SETTABLE, cc.t.u.info, rkkey, lcode.luaK_exp2RK(fs, val)); + fs.freereg = reg; /* free registers */ +}; + +const closelistfield = function(fs, cc) { + if (cc.v.k === expkind.VVOID) return; /* there is no list item */ + lcode.luaK_exp2nextreg(fs, cc.v); + cc.v.k = expkind.VVOID; + if (cc.tostore === lopcode.LFIELDS_PER_FLUSH) { + luaK_setlist(fs, cc.t.u.info, cc.na, cc.tostore); /* flush */ + cc.tostore = 0; /* no more items pending */ + } +}; + +const lastlistfield = function(fs, cc) { + if (cc.tostore === 0) return; + if (hasmultret(cc.v.k)) { + lcode.luaK_setmultret(fs, cc.v); + lcode.luaK_setlist(fs, cc.t.u.info, cc.na, lua.LUA_MULTRET); + cc.na--; /* do not count last expression (unknown number of elements) */ + } else { + if (cc.v.k !== expkind.VVOID) + lcode.luaK_exp2nextreg(fs, cc.v); + lcode.luaK_setlist(fs, cc.t.u.info, cc.na, cc.tostore); + } +}; + +const listfield = function(ls, cc) { + /* listfield -> exp */ + expr(ls, cc.v); + checklimit(ls.fs, cc.na, Number.MAX_SAFE_INTEGER, "items in a constructor"); + cc.na++; + cc.tostore++; +}; + +const field = function(ls, cc) { + /* field -> listfield | recfield */ + switch (ls.t.token) { + case R.TK_NAME: { /* may be 'listfield' or 'recfield' */ + if (llex.luaX_lookahead(ls) !== '=') /* expression? */ + listfield(ls, cc); + else + recfield(ls, cc); + break; + } + case '[': { + recfield(ls, cc); + break; + } + default: { + listfield(ls, cc); + break; + } + } +}; + +const constructor = function(ls, t) { + /* constructor -> '{' [ field { sep field } [sep] ] '}' + sep -> ',' | ';' */ + let fs = ls.fs; + let line = ls.linenumber; + let pc = lcode.luaK_codeABC(fs, OpCodesI.OP_NEWTABLE, 0, 0, 0); + let cc = new ConsControl(); + cc.na = cc.nh = cc.tostore = 0; + cc.t = t; + init_exp(t, expkind.VRELOCABLE, pc); + init_exp(cc.v, expkind.VVOID, 0); /* no value (yet) */ + lcode.luaK_exp2nextreg(ls.fs, t); /* fix it at stack top */ + checknext(ls, '{'); + do { + assert(cc.v.k === expkind.VVOID || cc.tostore > 0); + if (ls.t.token === '}') break; + closelistfield(fs, cc); + field(ls, cc); + } while (testnext(ls, ',') || testnext(ls, ';')); + check_match(ls, '}', '{', line); + lastlistfield(fs, cc); + lopcode.SETARG_B(fs.f.code[pc], lobject.luaO_int2fb(cc.na)); /* set initial array size */ + lopcode.SETARG_C(fs.f.code[pc], lobject.luaO_int2fb(cc.nh)); /* set initial table size */ +}; + +/* +** {====================================================================== +** Expression parsing +** ======================================================================= +*/ + +const simpleexp = function(ls, v) { + /* simpleexp -> FLT | INT | STRING | NIL | TRUE | FALSE | ... | + constructor | FUNCTION body | suffixedexp */ + switch (ls.t.token) { + case R.TK_FLT: { + init_exp(v, expkind.VFLT, 0); + v.u.nval = ls.t.seminfo.r; + break; + } + case R.TK_INT: { + init_exp(v, expkind.VKINT, 0); + v.u.ival = ls.t.seminfo.i; + break; + } + case R.TK_STRING: { + codestring(ls, v, ls.t.seminfo.ts); + break; + } + case R.TK_NIL: { + init_exp(v, expkind.VNIL, 0); + break; + } + case R.TK_TRUE: { + init_exp(v, expkind.VTRUE, 0); + break; + } + case R.TK_FALSE: { + init_exp(v, expkind.VFALSE, 0); + break; + } + case R.TK_DOTS: { /* vararg */ + let fs = ls.fs; + check_condition(ls, fs.f.is_vararg, "cannot use '...' outside a vararg function"); + init_exp(v, expkind.VVARARG, lcode.luaK_codeABC(fs, OpCodesI.OP_VARARG, 0, 1, 0)); + } + case '{': { /* constructor */ + constructor(ls, v); + return; + } + case R.TK_FUNCTION: { + llex.luaX_next(ls); + body(ls, v, 0, ls.linenumber); + return; + } + default: { + suffixedexp(ls, v); + return; + } + } + llex.luaX_next(ls); +}; + +const getunopr = function(op) { + switch (op) { + case R.TK_NOT: return UnOpr.OPR_NOT; + case '-': return UnOpr.OPR_MINUS; + case '~': return UnOpr.OPR_BNOT; + case '#': return UnOpr.OPR_LEN; + default: return UnOpr.OPR_NOUNOPR; + } +}; + +const getbinopr = function(op) { + switch (op) { + case '+': return BinOpr.OPR_ADD; + case '-': return BinOpr.OPR_SUB; + case '*': return BinOpr.OPR_MUL; + case '%': return BinOpr.OPR_MOD; + case '^': return BinOpr.OPR_POW; + case '/': return BinOpr.OPR_DIV; + case R.TK_IDIV: return BinOpr.OPR_IDIV; + case '&': return BinOpr.OPR_BAND; + case '|': return BinOpr.OPR_BOR; + case '~': return BinOpr.OPR_BXOR; + case R.TK_SHL: return BinOpr.OPR_SHL; + case R.TK_SHR: return BinOpr.OPR_SHR; + case R.TK_CONCAT: return BinOpr.OPR_CONCAT; + case R.TK_NE: return BinOpr.OPR_NE; + case R.TK_EQ: return BinOpr.OPR_EQ; + case '<': return BinOpr.OPR_LT; + case R.TK_LE: return BinOpr.OPR_LE; + case '>': return BinOpr.OPR_GT; + case R.TK_GE: return BinOpr.OPR_GE; + case R.TK_AND: return BinOpr.OPR_AND; + case R.TK_OR: return BinOpr.OPR_OR; + default: return BinOpr.OPR_NOBINOPR; + } +}; + +const priority = [ /* ORDER OPR */ + {10, 10}, {10, 10}, /* '+' '-' */ + {11, 11}, {11, 11}, /* '*' '%' */ + {14, 13}, /* '^' (right associative) */ + {11, 11}, {11, 11}, /* '/' '//' */ + {6, 6}, {4, 4}, {5, 5}, /* '&' '|' '~' */ + {7, 7}, {7, 7}, /* '<<' '>>' */ + {9, 8}, /* '..' (right associative) */ + {3, 3}, {3, 3}, {3, 3}, /* ==, <, <= */ + {3, 3}, {3, 3}, {3, 3}, /* ~=, >, >= */ + {2, 2}, {1, 1} /* and, or */ +]; + +const UNARY_PRIORITY = 12; + +/* +** subexpr -> (simpleexp | unop subexpr) { binop subexpr } +** where 'binop' is any binary operator with a priority higher than 'limit' +*/ +const subexpr = function(ls, v, limit) { + enterlevel(ls); + let uop = getunopr(ls.t.token); + if (uop !== UnOpr.OPR_NOUNOPR) { + let line = ls.linenumber; + llex.luaX_next(ls); + subexpr(ls, v, UNARY_PRIORITY); + lcode.luaK_prefix(ls.fs, uop, v, line); + } else + simpleexp(ls, v); + /* expand while operators have priorities higher than 'limit' */ + let op = getbinopr(ls.t.token); + while (op !== BinOpr.OPR_NOBINOPR && priority[op].left > limit) { + let v2 = new expdesc(); + let line = ls.linenumber; + llex.luaX_next(ls); + lcode.luaK_infix(ls.fs, op, v); + /* read sub-expression with higher priority */ + let nextop = subexpr(ls, v2, priority[op].right); + lcode.luaK_posfix(ls.fs, op, v, v2, line); + op = nextop; + } + leavelevel(ls); + return op; /* return first untreated operator */ +}; + +const expr = function(ls, v) { + subexpr(ls, v, 0); +} + +const test_then_block = function(ls, escapelist) { + /* test_then_block -> [IF | ELSEIF] cond THEN block */ + let bl = new BlockCnt(); + let fs = ls.fs; + let v = new expdesc(); + let jf; /* instruction to skip 'then' code (if condition is false) */ + + llex.luaX_next(ls); /* skip IF or ELSEIF */ + expr(ls, v); /* read condition */ + checknext(ls, R.TK_THEN); + + if (ls.t.token === R.TK_GOTO || ls.t.token === R.TK_BREAK) { + lcode.luaK_goiffalse(ls.fs, v); /* will jump to label if condition is true */ + enterblock(fs, bl, false); /* must enter block before 'goto' */ + gotostat(ls, v.t); /* handle goto/break */ + skipnoopstat(ls); /* skip other no-op statements */ + if (block_follow(ls, 0)) { /* 'goto' is the entire block? */ + leaveblock(fs); + return; /* and that is it */ + } else /* must skip over 'then' part if condition is false */ + jf = lcode.luaK_jump(fs); + } else { /* regular case (not goto/break) */ + lcode.luaK_goiftrue(ls.fs, v); /* skip over block if condition is false */ + enterblock(fs, bl, false); + jf = v.f; + } + + statlist(ls); /* 'then' part */ + leaveblock(fs); + if (ls.t.token === R.TK_ELSE || ls.t.token === R.TK_ELSEIF) /* followed by 'else'/'elseif'? */ + escapelist = lcode.luaK_concat(fs, escapelist, lcode.luaK_jump(fs)); /* must jump over it */ + lcode.luaK_patchtohere(fs, jf); +}; + +const ifstat = function(ls, line) { + /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */ + let fs = ls.fs; + let escapelist = lcode.NO_JUMP; /* exit list for finished parts */ + test_then_block(ls, escapelist); /* IF cond THEN block */ + while (ls.t.token === R.TK_ELSEIF) + test_then_block(ls, escapelist); /* ELSEIF cond THEN block */ + if (testnext(ls, R.TK_ELSE)) + block(ls); /* 'else' part */ + check_match(ls, R.TK_END, R.TK_IF, line); + lcode.luaK_patchtohere(fs, escapelist); /* patch escape list to 'if' end */ +}; + +const statement = function(ls) { + let line = ls.linenumber; /* may be needed for error messages */ + enterlevel(ls); + switch(ls.t.token) { + case ';': { /* stat -> ';' (empty statement) */ + llex.luaX_next(ls); /* skip ';' */ + break; + } + case R.TK_IF: { /* stat -> ifstat */ + ifstat(ls, line); + break; + } + case R.TK_WHILE: { /* stat -> whilestat */ + whilestat(ls, line); + break; + } + case R.TK_DO: { /* stat -> DO block END */ + llex.luaX_next(ls); /* skip DO */ + block(ls); + check_match(ls, R.TK_END, R.TK_DO, line); + break; + } + case R.TK_FOR: { /* stat -> forstat */ + forstat(ls, line); + break; + } + case R.TK_REPEAT: { /* stat -> repeatstat */ + repeatstat(ls, line); + break; + } + case R.TK_FUNCTION: { /* stat -> funcstat */ + funcstat(ls, line); + break; + } + case R.TK_LOCAL: { /* stat -> localstat */ + llex.luaX_next(ls); /* skip LOCAL */ + if (testnext(ls, R.TK_FUNCTION)) /* local function? */ + localfunc(ls); + else + localstat(ls); + break; + } + case R.TK_DBCOLON: { /* stat -> label */ + llex.luaX_next(ls); /* skip double colon */ + labelstat(ls, str_checkname(ls), line); + break; + } + case R.TK_RETURN: { /* skip double colon */ + llex.luaX_next(ls); /* skip RETURN */ + retstat(ls); + break; + } + case R.TK_BREAK: /* stat -> breakstat */ + case R.TK_GOTO: { /* stat -> 'goto' NAME */ + gotostat(ls, lcode.luaK_jump(ls.fs)); + break; + } + default: { /* stat -> func | assignment */ + exprstat(ls); + break; + } + } + + assert(ls.fs.f.maxstacksize >= ls.fs.freereg && ls.fs.freereg >= ls.fs.nactvar); + ls.fs.freereg = ls.fs.nactvar; /* free registers */ + leavelevel(ls); +}; + /* ** compiles the main function, which is a regular vararg function with an ** upvalue named LUA_ENV |