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hscript-improved/hscript/Parser.hx
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14 KiB
Haxe

/*
* Copyright (c) 2008, Nicolas Cannasse
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE HAXE PROJECT CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE HAXE PROJECT CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*/
package hscript;
import hscript.Expr;
enum Token {
TEof;
TConst( c : Const );
TId( s : String );
TOp( s : String );
TPOpen;
TPClose;
TBrOpen;
TBrClose;
TDot;
TComma;
TSemicolon;
TBkOpen;
TBkClose;
TQuestion;
TDoubleDot;
}
class Parser {
// config / variables
public var line : Int;
public var opChars : String;
public var identChars : String;
public var opPriority : Array<String>;
public var unopsPrefix : Array<String>;
public var unopsSuffix : Array<String>;
// implementation
var char : Null<Int>;
var ops : Array<Bool>;
var idents : Array<Bool>;
var tokens : haxe.FastList<Token>;
public function new() {
line = 1;
opChars = "+*/-=!><&|^%";
identChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_";
opPriority = [
"...",
"=",
"||","&&",
"==","!=",">","<",">=","<=",
"|","&","^",
"<<",">>",">>>",
"+","-",
"*","/",
"%"
];
unopsPrefix = ["!","++","--","-"];
unopsSuffix = ["++","--"];
}
public function parseString( s : String ) {
line = 1;
return parse( new haxe.io.StringInput(s) );
}
public function parse( s : haxe.io.Input ) {
char = null;
ops = new Array();
idents = new Array();
tokens = new haxe.FastList<Token>();
for( i in 0...opChars.length )
ops[opChars.charCodeAt(i)] = true;
for( i in 0...identChars.length )
idents[identChars.charCodeAt(i)] = true;
var a = new Array();
while( true ) {
var tk = token(s);
if( tk == TEof ) break;
tokens.add(tk);
a.push(parseFullExpr(s));
}
return if( a.length == 1 ) a[0] else EBlock(a);
}
function unexpected( tk ) : Dynamic {
throw Error.EUnexpected(tokenString(tk));
return null;
}
function isBlock(e) {
return switch( e ) {
case EBlock(_): true;
case EFunction(_,e,_): isBlock(e);
case EVar(_,e): e != null && isBlock(e);
case EIf(_,e1,e2): if( e2 != null ) isBlock(e2) else isBlock(e1);
case EBinop(_,_,e): isBlock(e);
case EUnop(_,prefix,e): !prefix && isBlock(e);
case EWhile(_,e): isBlock(e);
case EFor(_,_,e): isBlock(e);
case EReturn(e): e != null && isBlock(e);
default: false;
}
}
function parseFullExpr(s) {
var e = parseExpr(s);
var tk = token(s);
if( tk != TSemicolon && tk != TEof ) {
if( isBlock(e) )
tokens.add(tk);
else
unexpected(tk);
}
return e;
}
function parseExpr( s : haxe.io.Input ) {
var tk = token(s);
switch( tk ) {
case TId(id):
var e = parseStructure(s,id);
if( e == null )
e = EIdent(id);
return parseExprNext(s,e);
case TConst(c):
return parseExprNext(s,EConst(c));
case TPOpen:
var e = parseExpr(s);
tk = token(s);
if( tk != TPClose ) unexpected(tk);
return parseExprNext(s,EParent(e));
case TBrOpen:
var a = new Array();
while( true ) {
tk = token(s);
if( tk == TBrClose )
break;
tokens.add(tk);
a.push(parseFullExpr(s));
}
return EBlock(a);
case TOp(op):
var found;
for( x in unopsPrefix )
if( x == op )
return makeUnop(op,parseExpr(s));
return unexpected(tk);
case TBkOpen:
return parseExprNext(s,EArrayDecl(parseExprList(s,TBkClose)));
default:
return unexpected(tk);
}
}
function priority(op) {
for( i in 0...opPriority.length )
if( opPriority[i] == op )
return i;
return -1;
}
function makeUnop( op, e ) {
return switch( e ) {
case EBinop(bop,e1,e2): EBinop(bop,makeUnop(op,e1),e2);
default: EUnop(op,true,e);
}
}
function makeBinop( op, e1, e2 ) {
return switch( e2 ) {
case EBinop(op2,e2,e3):
if( priority(op) > priority(op2) )
return EBinop(op2,makeBinop(op,e1,e2),e3);
default: EBinop(op,e1,e2);
}
}
function parseStructure( s, id ) {
return switch( id ) {
case "if":
var cond = parseExpr(s);
var e1 = parseExpr(s);
var e2 = null;
var semic = false;
var tk = token(s);
if( tk == TSemicolon ) {
semic = true;
tk = token(s);
}
if( Type.enumEq(tk,TId("else")) )
e2 = parseExpr(s);
else {
tokens.add(tk);
if( semic ) tokens.add(TSemicolon);
}
EIf(cond,e1,e2);
case "var":
var tk = token(s);
var ident = null;
switch(tk) {
case TId(id): ident = id;
default: unexpected(tk);
}
tk = token(s);
var e = null;
if( Type.enumEq(tk,TOp("=")) )
e = parseExpr(s);
else
tokens.add(tk);
EVar(ident,e);
case "while":
var econd = parseExpr(s);
var e = parseExpr(s);
EWhile(econd,e);
case "for":
var tk = token(s);
if( tk != TPOpen ) unexpected(tk);
tk = token(s);
var vname = null;
switch( tk ) {
case TId(id): vname = id;
default: unexpected(tk);
}
tk = token(s);
if( !Type.enumEq(tk,TId("in")) ) unexpected(tk);
var eiter = parseExpr(s);
tk = token(s);
if( tk != TPClose ) unexpected(tk);
EFor(vname,eiter,parseExpr(s));
case "break": EBreak;
case "continue": EContinue;
case "else": unexpected(TId(id));
case "function":
var tk = token(s);
var name = null;
switch( tk ) {
case TId(id): name = id; tk = token(s);
default:
}
if( tk != TPOpen ) unexpected(tk);
var args = new Array();
tk = token(s);
if( tk != TPClose ) {
while( true ) {
switch( tk ) {
case TId(id): args.push(id);
default: unexpected(tk);
}
tk = token(s);
switch( tk ) {
case TComma:
case TPClose: break;
default: unexpected(tk);
}
tk = token(s);
}
}
EFunction(args,parseExpr(s),name);
case "return":
var tk = token(s);
tokens.add(tk);
EReturn(if( tk == TSemicolon ) null else parseExpr(s));
case "new":
var a = new Array();
var tk = token(s);
switch( tk ) {
case TId(id): a.push(id);
default: unexpected(tk);
}
while( true ) {
tk = token(s);
switch( tk ) {
case TDot:
tk = token(s);
switch(tk) {
case TId(id): a.push(id);
default: unexpected(tk);
}
case TPOpen:
break;
default:
unexpected(tk);
}
}
ENew(a.join("."),parseExprList(s,TPClose));
case "throw":
EThrow( parseExpr(s) );
case "try":
var e = parseExpr(s);
var tk = token(s);
if( !Type.enumEq(tk,TId("catch")) ) unexpected(tk);
tk = token(s);
if( tk != TPOpen ) unexpected(tk);
tk = token(s);
var vname = switch( tk ) {
case TId(id): id;
default: unexpected(tk);
}
tk = token(s);
if( tk != TDoubleDot ) unexpected(tk);
tk = token(s);
if( !Type.enumEq(tk,TId("Dynamic")) ) unexpected(tk);
tk = token(s);
if( tk != TPClose ) unexpected(tk);
ETry(e,vname,parseExpr(s));
default:
null;
}
}
function parseExprNext( s : haxe.io.Input, e1 : Expr ) {
var tk = token(s);
switch( tk ) {
case TOp(op):
for( x in unopsSuffix )
if( x == op )
return EUnop(op,false,e1);
return makeBinop(op,e1,parseExpr(s));
case TDot:
tk = token(s);
var field = null;
switch(tk) {
case TId(id): field = id;
default: unexpected(tk);
}
return parseExprNext(s,EField(e1,field));
case TPOpen:
return parseExprNext(s,ECall(e1,parseExprList(s,TPClose)));
case TBkOpen:
var e2 = parseExpr(s);
tk = token(s);
if( tk != TBkClose ) unexpected(tk);
return parseExprNext(s,EArray(e1,e2));
case TQuestion:
var e2 = parseExpr(s);
tk = token(s);
if( tk != TDoubleDot ) unexpected(tk);
var e3 = parseExpr(s);
return EIf(e1,e2,e3);
default:
tokens.add(tk);
return e1;
}
}
function parseExprList( s : haxe.io.Input, etk ) {
var args = new Array();
var tk = token(s);
if( tk == etk )
return args;
tokens.add(tk);
while( true ) {
args.push(parseExpr(s));
tk = token(s);
switch( tk ) {
case TComma:
default:
if( tk == etk ) break;
unexpected(tk);
}
}
return args;
}
function readChar( s : haxe.io.Input ) {
return try s.readByte() catch( e : Dynamic ) 0;
}
function readString( s : haxe.io.Input, until ) {
var c;
var b = new StringBuf();
var esc = false;
var old = line;
while( true ) {
try {
c = s.readByte();
} catch( e : Dynamic ) {
line = old;
throw Error.EUnterminatedString;
}
if( esc ) {
esc = false;
switch( c ) {
case 110: b.addChar(10); // \n
case 114: b.addChar(13); // \r
case 116: b.addChar(9); // \t
case 39: b.addChar(39); // \'
case 34: b.addChar(34); // \"
case 92: b.addChar(92); // \\
default: throw Error.EInvalidChar(c);
}
} else if( c == 92 )
esc = true;
else if( c == until )
break;
else {
if( c == 10 ) line++;
b.addChar(c);
}
}
return b.toString();
}
function token( s : haxe.io.Input ) {
if( !tokens.isEmpty() )
return tokens.pop();
var char;
if( this.char == null )
char = readChar(s);
else {
char = this.char;
this.char = null;
}
while( true ) {
switch( char ) {
case 0: return TEof;
case 32,9,13: // space, tab, CR
case 10: line++; // LF
case 48,49,50,51,52,53,54,55,56,57: // 0...9
var n = char - 48;
var exp = 0;
while( true ) {
char = readChar(s);
exp *= 10;
switch( char ) {
case 48,49,50,51,52,53,54,55,56,57:
n = n * 10 + (char - 48);
case 46:
if( exp > 0 ) {
// in case of '...'
if( exp == 10 && readChar(s) == 46 ) {
tokens.add(TOp("..."));
return TConst( CInt(n) );
}
throw Error.EInvalidChar(char);
}
exp = 1;
case 120: // x
if( n > 0 || exp > 0 )
throw Error.EInvalidChar(char);
// read hexa
while( true ) {
char = readChar(s);
switch( char ) {
case 48,49,50,51,52,53,54,55,56,57: // 0-9
n = (n << 4) + (char - 48);
case 65,66,67,68,69,70: // A-F
n = (n << 4) + (char - 55);
case 97,98,99,100,101,102: // a-f
n = (n << 4) + (char - 87);
default:
this.char = char;
return TConst( CInt(n) );
}
}
default:
this.char = char;
return TConst( (exp > 0) ? CFloat(n * 10 / exp) : CInt(n) );
}
}
case 59: return TSemicolon;
case 40: return TPOpen;
case 41: return TPClose;
case 44: return TComma;
case 46:
char = readChar(s);
if( char != 46 ) {
this.char = char;
return TDot;
}
char = readChar(s);
if( char != 46 )
throw Error.EInvalidChar(char);
return TOp("...");
case 123: return TBrOpen;
case 125: return TBrClose;
case 91: return TBkOpen;
case 93: return TBkClose;
case 39: return TConst( CString(readString(s,39)) );
case 34: return TConst( CString(readString(s,34)) );
case 63: return TQuestion;
case 58: return TDoubleDot;
default:
if( ops[char] ) {
var op = String.fromCharCode(char);
while( true ) {
char = readChar(s);
if( !ops[char] ) {
if( op.charCodeAt(0) == 47 )
return tokenComment(s,op,char);
this.char = char;
return TOp(op);
}
op += String.fromCharCode(char);
}
}
if( idents[char] ) {
var id = String.fromCharCode(char);
while( true ) {
char = readChar(s);
if( !idents[char] ) {
this.char = char;
return TId(id);
}
id += String.fromCharCode(char);
}
}
throw Error.EInvalidChar(char);
}
char = readChar(s);
}
return null;
}
function tokenComment( s : haxe.io.Input, op : String, char : Int ) {
var c = op.charCodeAt(1);
if( c == 47 ) { // comment
try {
while( char != 10 && char != 13 )
char = s.readByte();
this.char = char;
} catch( e : Dynamic ) {
}
return token(s);
}
if( c == 42 ) { /* comment */
var old = line;
try {
while( true ) {
while( char != 42 ) {
if( char == 10 ) line++;
char = s.readByte();
}
char = s.readByte();
if( char == 47 )
break;
}
} catch( e : Dynamic ) {
line = old;
throw Error.EUnterminatedComment;
}
return token(s);
}
return TOp(op);
}
function constString( c ) {
return switch(c) {
case CInt(v): Std.string(v);
case CFloat(f): Std.string(f);
case CString(s): s; // TODO : escape + quote
}
}
function tokenString( t ) {
return switch( t ) {
case TEof: "<eof>";
case TConst(c): constString(c);
case TId(s): s;
case TOp(s): s;
case TPOpen: "(";
case TPClose: ")";
case TBrOpen: "{";
case TBrClose: "}";
case TDot: ".";
case TComma: ",";
case TSemicolon: ";";
case TBkOpen: "[";
case TBkClose: "]";
case TQuestion: "?";
case TDoubleDot: ":";
}
}
}