shithub: libmujs

ref: 948d6a9fa86fa0e10f0a7674873ac08f0627a173
dir: /js-parse.c/

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#include "js.h"
#include "js-parse.h"
#include "js-ast.h"

#define A1(x,a)		jsP_newnode(J, x, a, 0, 0, 0)
#define A2(x,a,b)	jsP_newnode(J, x, a, b, 0, 0)
#define A3(x,a,b,c)	jsP_newnode(J, x, a, b, c, 0)

#define LIST(h)		jsP_newnode(J, AST_LIST, h, 0, 0, 0);

#define EXP0(x)		jsP_newnode(J, EXP_ ## x, 0, 0, 0, 0)
#define EXP1(x,a)	jsP_newnode(J, EXP_ ## x, a, 0, 0, 0)
#define EXP2(x,a,b)	jsP_newnode(J, EXP_ ## x, a, b, 0, 0)
#define EXP3(x,a,b,c)	jsP_newnode(J, EXP_ ## x, a, b, c, 0)

#define STM0(x)		jsP_newnode(J, STM_ ## x, 0, 0, 0, 0)
#define STM1(x,a)	jsP_newnode(J, STM_ ## x, a, 0, 0, 0)
#define STM2(x,a,b)	jsP_newnode(J, STM_ ## x, a, b, 0, 0)
#define STM3(x,a,b,c)	jsP_newnode(J, STM_ ## x, a, b, c, 0)
#define STM4(x,a,b,c,d)	jsP_newnode(J, STM_ ## x, a, b, c, d)

static js_Ast *expression(js_State *J, int notin);
static js_Ast *assignment(js_State *J, int notin);
static js_Ast *memberexp(js_State *J);
static js_Ast *statement(js_State *J);
static js_Ast *functionbody(js_State *J);

static const char *tokenstring[] = {
	"(end-of-file)",
	"'\\x01'", "'\\x02'", "'\\x03'", "'\\x04'", "'\\x05'", "'\\x06'", "'\\x07'",
	"'\\x08'", "'\\x09'", "'\\x0A'", "'\\x0B'", "'\\x0C'", "'\\x0D'", "'\\x0E'", "'\\x0F'",
	"'\\x10'", "'\\x11'", "'\\x12'", "'\\x13'", "'\\x14'", "'\\x15'", "'\\x16'", "'\\x17'",
	"'\\x18'", "'\\x19'", "'\\x1A'", "'\\x1B'", "'\\x1C'", "'\\x1D'", "'\\x1E'", "'\\x1F'",
	"' '", "'!'", "'\"'", "'#'", "'$'", "'%'", "'&'", "'\\''",
	"'('", "')'", "'*'", "'+'", "','", "'-'", "'.'", "'/'",
	"'0'", "'1'", "'2'", "'3'", "'4'", "'5'", "'6'", "'7'",
	"'8'", "'9'", "':'", "';'", "'<'", "'='", "'>'", "'?'",
	"'@'", "'A'", "'B'", "'C'", "'D'", "'E'", "'F'", "'G'",
	"'H'", "'I'", "'J'", "'K'", "'L'", "'M'", "'N'", "'O'",
	"'P'", "'Q'", "'R'", "'S'", "'T'", "'U'", "'V'", "'W'",
	"'X'", "'Y'", "'Z'", "'['", "'\'", "']'", "'^'", "'_'",
	"'`'", "'a'", "'b'", "'c'", "'d'", "'e'", "'f'", "'g'",
	"'h'", "'i'", "'j'", "'k'", "'l'", "'m'", "'n'", "'o'",
	"'p'", "'q'", "'r'", "'s'", "'t'", "'u'", "'v'", "'w'",
	"'x'", "'y'", "'z'", "'{'", "'|'", "'}'", "'~'", "'\\x7F'",

	0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
	0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
	0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
	0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
	0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
	0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
	0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
	0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,

	"(identifier)", "(number)", "(string)", "(regexp)",

	"'<='", "'>='", "'=='", "'!='", "'==='", "'!=='",
	"'<<'", "'>>'", "'>>>'", "'&&'", "'||'",
	"'+='", "'-='", "'*='", "'/='", "'%='",
	"'<<='", "'>>='", "'>>>='", "'&='", "'|='", "'^='",
	"'++'", "'--'",

	"'break'", "'case'", "'catch'", "'continue'", "'debugger'",
	"'default'", "'delete'", "'do'", "'else'", "'false'", "'finally'", "'for'",
	"'function'", "'if'", "'in'", "'instanceof'", "'new'", "'null'", "'return'",
	"'switch'", "'this'", "'throw'", "'true'", "'try'", "'typeof'", "'var'",
	"'void'", "'while'", "'with'",
};

static inline void next(js_State *J)
{
	J->lookahead = jsP_lex(J);
}

static inline int accept(js_State *J, int t)
{
	if (J->lookahead == t) {
		next(J);
		return 1;
	}
	return 0;
}

static inline void expect(js_State *J, int t)
{
	if (accept(J, t))
		return;
	jsP_error(J, "unexpected token: %s (expected %s)", tokenstring[J->lookahead], tokenstring[t]);
}

static void semicolon(js_State *J)
{
	if (J->lookahead == ';') {
		next(J);
		return;
	}
	if (J->newline || J->lookahead == '}' || J->lookahead == 0)
		return;
	jsP_error(J, "unexpected token: %s (expected ';')", tokenstring[J->lookahead]);
}

static js_Ast *identifier(js_State *J)
{
	if (J->lookahead == TK_IDENTIFIER) {
		js_Ast *a = jsP_newstrnode(J, AST_IDENTIFIER, J->text);
		next(J);
		return a;
	}
	jsP_error(J, "unexpected token: %s (expected identifier)", tokenstring[J->lookahead]);
	return NULL;
}

static js_Ast *identifieropt(js_State *J)
{
	if (J->lookahead == TK_IDENTIFIER)
		return identifier(J);
	return NULL;
}

static js_Ast *identifiername(js_State *J)
{
	if (J->lookahead == TK_IDENTIFIER || J->lookahead >= TK_BREAK) {
		js_Ast *a = jsP_newstrnode(J, AST_IDENTIFIER, J->text);
		next(J);
		return a;
	}
	jsP_error(J, "unexpected token: %s (expected identifier or keyword)", tokenstring[J->lookahead]);
	return NULL;
}

static js_Ast *arguments(js_State *J)
{
	js_Ast *head, *tail, *node;

	if (J->lookahead == ')')
		return NULL;

	node = assignment(J, 0);
	head = tail = LIST(node);
	while (accept(J, ',')) {
		node = assignment(J, 0);
		tail = tail->b = LIST(node);
	}
	return head;
}

static js_Ast *arrayliteral(js_State *J)
{
	js_Ast *head, *tail, *node;

	while (J->lookahead == ',')
		next(J);

	if (J->lookahead == ']')
		return NULL;

	node = assignment(J, 0);
	head = tail = LIST(node);
	while (accept(J, ',')) {
		while (J->lookahead == ',')
			next(J);
		if (J->lookahead == ']')
			break;
		node = assignment(J, 0);
		tail = tail->b = LIST(node);
	}
	return head;
}

static js_Ast *propname(js_State *J)
{
	js_Ast *name;
	if (J->lookahead == TK_NUMBER) {
		name = jsP_newnumnode(J, AST_NUMBER, J->number);
		next(J);
	} else if (J->lookahead == TK_STRING) {
		name = jsP_newstrnode(J, AST_STRING, J->text);
		next(J);
	} else {
		name = identifiername(J);
	}
	return name;
}

static js_Ast *propassign(js_State *J)
{
	js_Ast *name, *value, *arg, *body;

	if (J->lookahead == TK_IDENTIFIER && !strcmp(J->text, "get")) {
		next(J);
		name = propname(J);
		expect(J, '(');
		expect(J, ')');
		body = functionbody(J);
		return EXP2(PROP_GET, name, body);
	}

	if (J->lookahead == TK_IDENTIFIER && !strcmp(J->text, "set")) {
		next(J);
		name = propname(J);
		expect(J, '(');
		arg = identifier(J);
		expect(J, ')');
		body = functionbody(J);
		return EXP3(PROP_SET, name, arg, body);
	}

	name = propname(J);
	expect(J, ':');
	value = assignment(J, 0);
	return EXP2(PROP_VAL, name, value);
}

static js_Ast *objectliteral(js_State *J)
{
	js_Ast *head, *tail, *node;

	if (J->lookahead == '}')
		return NULL;

	node = propassign(J);
	head = tail = LIST(node);
	while (accept(J, ',')) {
		if (J->lookahead == '}')
			break;
		node = propassign(J);
		tail = tail->b = LIST(node);
	}
	return head;
}

static js_Ast *primary(js_State *J)
{
	js_Ast *a;
	if (J->lookahead == TK_IDENTIFIER) {
		a = jsP_newstrnode(J, AST_IDENTIFIER, J->text);
		next(J);
		return a;
	}
	if (J->lookahead == TK_STRING) {
		a = jsP_newstrnode(J, AST_STRING, J->text);
		next(J);
		return a;
	}
	if (J->lookahead == TK_REGEXP) {
		a = jsP_newstrnode(J, AST_REGEXP, J->text);
		// TODO: flags
		next(J);
		return a;
	}
	if (J->lookahead == TK_NUMBER) {
		a = jsP_newnumnode(J, AST_NUMBER, J->number);
		next(J);
		return a;
	}
	if (accept(J, TK_THIS)) return EXP0(THIS);
	if (accept(J, TK_NULL)) return EXP0(NULL);
	if (accept(J, TK_TRUE)) return EXP0(TRUE);
	if (accept(J, TK_FALSE)) return EXP0(FALSE);
	if (accept(J, '{')) { a = EXP1(OBJECT, objectliteral(J)); expect(J, '}'); return a; }
	if (accept(J, '[')) { a = EXP1(ARRAY, arrayliteral(J)); expect(J, ']'); return a; }
	if (accept(J, '(')) { a = expression(J, 0); expect(J, ')'); return a; }
	jsP_error(J, "unexpected token in expression: %s", tokenstring[J->lookahead]);
	return NULL;
}

static js_Ast *paramlist(js_State *J)
{
	js_Ast *head, *tail, *node;

	if (J->lookahead == ')')
		return NULL;

	node = identifier(J);
	head = tail = LIST(node);
	while (accept(J, ',')) {
		node = identifier(J);
		tail = tail->b = LIST(node);
	}
	return head;
}

static js_Ast *newexp(js_State *J)
{
	js_Ast *a, *b, *c;
	if (accept(J, TK_NEW)) {
		a = memberexp(J);
		if (accept(J, '(')) {
			b = arguments(J);
			expect(J, ')');
			return EXP2(NEW, a, b);
		}
		return EXP1(NEW, a);
	}
	if (accept(J, TK_FUNCTION)) {
		a = identifieropt(J);
		expect(J, '(');
		b = paramlist(J);
		expect(J, ')');
		c = functionbody(J);
		return EXP3(FUNC, a, b, c);
	}
	return primary(J);
}

static js_Ast *memberexp(js_State *J)
{
	js_Ast *a = newexp(J);
loop:
	if (accept(J, '.')) { a = EXP2(MEMBER, a, identifiername(J)); goto loop; }
	if (accept(J, '[')) { a = EXP2(INDEX, a, expression(J, 0)); expect(J, ']'); goto loop; }
	return a;
}

static js_Ast *callexp(js_State *J)
{
	js_Ast *a = newexp(J);
loop:
	if (accept(J, '.')) { a = EXP2(MEMBER, a, identifiername(J)); goto loop; }
	if (accept(J, '[')) { a = EXP2(INDEX, a, expression(J, 0)); expect(J, ']'); goto loop; }
	if (accept(J, '(')) { a = EXP2(CALL, a, arguments(J)); expect(J, ')'); goto loop; }
	return a;
}

static js_Ast *postfix(js_State *J)
{
	js_Ast *a = callexp(J);
	if (!J->newline && accept(J, TK_INC)) return EXP1(POSTINC, a);
	if (!J->newline && accept(J, TK_DEC)) return EXP1(POSTDEC, a);
	return a;
}

static js_Ast *unary(js_State *J)
{
	if (accept(J, TK_DELETE)) return EXP1(DELETE, unary(J));
	if (accept(J, TK_VOID)) return EXP1(VOID, unary(J));
	if (accept(J, TK_TYPEOF)) return EXP1(TYPEOF, unary(J));
	if (accept(J, TK_INC)) return EXP1(PREINC, unary(J));
	if (accept(J, TK_DEC)) return EXP1(PREDEC, unary(J));
	if (accept(J, '+')) return EXP1(POS, unary(J));
	if (accept(J, '-')) return EXP1(NEG, unary(J));
	if (accept(J, '~')) return EXP1(BITNOT, unary(J));
	if (accept(J, '!')) return EXP1(LOGNOT, unary(J));
	return postfix(J);
}

static js_Ast *multiplicative(js_State *J)
{
	js_Ast *a = unary(J);
loop:
	if (accept(J, '*')) { a = EXP2(MUL, a, unary(J)); goto loop; }
	if (accept(J, '/')) { a = EXP2(DIV, a, unary(J)); goto loop; }
	if (accept(J, '%')) { a = EXP2(MOD, a, unary(J)); goto loop; }
	return a;
}

static js_Ast *additive(js_State *J)
{
	js_Ast *a = multiplicative(J);
loop:
	if (accept(J, '+')) { a = EXP2(ADD, a, multiplicative(J)); goto loop; }
	if (accept(J, '-')) { a = EXP2(SUB, a, multiplicative(J)); goto loop; }
	return a;
}

static js_Ast *shift(js_State *J)
{
	js_Ast *a = additive(J);
loop:
	if (accept(J, TK_SHL)) { a = EXP2(SHL, a, additive(J)); goto loop; }
	if (accept(J, TK_SHR)) { a = EXP2(SHR, a, additive(J)); goto loop; }
	if (accept(J, TK_USHR)) { a = EXP2(USHR, a, additive(J)); goto loop; }
	return a;
}

static js_Ast *relational(js_State *J, int notin)
{
	js_Ast *a = shift(J);
loop:
	if (accept(J, '<')) { a = EXP2(LT, a, shift(J)); goto loop; }
	if (accept(J, '>')) { a = EXP2(GT, a, shift(J)); goto loop; }
	if (accept(J, TK_LE)) { a = EXP2(LE, a, shift(J)); goto loop; }
	if (accept(J, TK_GE)) { a = EXP2(GE, a, shift(J)); goto loop; }
	if (accept(J, TK_INSTANCEOF)) { a = EXP2(INSTANCEOF, a, shift(J)); goto loop; }
	if (!notin && accept(J, TK_IN)) { a = EXP2(IN, a, shift(J)); goto loop; }
	return a;
}

static js_Ast *equality(js_State *J, int notin)
{
	js_Ast *a = relational(J, notin);
loop:
	if (accept(J, TK_EQ)) { a = EXP2(EQ, a, relational(J, notin)); goto loop; }
	if (accept(J, TK_NE)) { a = EXP2(NE, a, relational(J, notin)); goto loop; }
	if (accept(J, TK_EQ3)) { a = EXP2(EQ3, a, relational(J, notin)); goto loop; }
	if (accept(J, TK_NE3)) { a = EXP2(NE3, a, relational(J, notin)); goto loop; }
	return a;
}

static js_Ast *bitand(js_State *J, int notin)
{
	js_Ast *a = equality(J, notin);
	while (accept(J, '&'))
		a = EXP2(BITAND, a, equality(J, notin));
	return a;
}

static js_Ast *bitxor(js_State *J, int notin)
{
	js_Ast *a = bitand(J, notin);
	while (accept(J, '^'))
		a = EXP2(BITXOR, a, bitand(J, notin));
	return a;
}

static js_Ast *bitor(js_State *J, int notin)
{
	js_Ast *a = bitxor(J, notin);
	while (accept(J, '|'))
		a = EXP2(BITOR, a, bitxor(J, notin));
	return a;
}

static js_Ast *logand(js_State *J, int notin)
{
	js_Ast *a = bitor(J, notin);
	while (accept(J, TK_AND))
		a = EXP2(LOGAND, a, bitor(J, notin));
	return a;
}

static js_Ast *logor(js_State *J, int notin)
{
	js_Ast *a = logand(J, notin);
	while (accept(J, TK_OR))
		a = EXP2(LOGOR, a, logand(J, notin));
	return a;
}

static js_Ast *conditional(js_State *J, int notin)
{
	js_Ast *a, *b, *c;
	a = logor(J, notin);
	if (accept(J, '?')) {
		b = assignment(J, notin);
		expect(J, ':');
		c = assignment(J, notin);
		return EXP3(COND, a, b, c);
	}
	return a;
}

static js_Ast *assignment(js_State *J, int notin)
{
	js_Ast *a = conditional(J, notin);
	if (accept(J, '=')) return EXP2(ASS, a, assignment(J, notin));
	if (accept(J, TK_MUL_ASS)) return EXP2(ASS_MUL, a, assignment(J, notin));
	if (accept(J, TK_DIV_ASS)) return EXP2(ASS_DIV, a, assignment(J, notin));
	if (accept(J, TK_MOD_ASS)) return EXP2(ASS_MOD, a, assignment(J, notin));
	if (accept(J, TK_ADD_ASS)) return EXP2(ASS_ADD, a, assignment(J, notin));
	if (accept(J, TK_SUB_ASS)) return EXP2(ASS_SUB, a, assignment(J, notin));
	if (accept(J, TK_SHL_ASS)) return EXP2(ASS_SHL, a, assignment(J, notin));
	if (accept(J, TK_SHR_ASS)) return EXP2(ASS_SHR, a, assignment(J, notin));
	if (accept(J, TK_USHR_ASS)) return EXP2(ASS_USHR, a, assignment(J, notin));
	if (accept(J, TK_AND_ASS)) return EXP2(ASS_BITAND, a, assignment(J, notin));
	if (accept(J, TK_XOR_ASS)) return EXP2(ASS_BITXOR, a, assignment(J, notin));
	if (accept(J, TK_OR_ASS)) return EXP2(ASS_BITOR, a, assignment(J, notin));
	return a;
}

static js_Ast *expression(js_State *J, int notin)
{
	js_Ast *a = assignment(J, notin);
	while (accept(J, ','))
		a = EXP2(COMMA, a, assignment(J, notin));
	return a;
}

static js_Ast *vardec(js_State *J, int notin)
{
	js_Ast *a, *b;

	a = identifier(J);
	if (accept(J, '='))
		b = assignment(J, notin);
	else
		b = NULL;

	return A2(AST_INIT, a, b);

}

static js_Ast *vardeclist(js_State *J, int notin)
{
	js_Ast *head, *tail, *node;

	node = vardec(J, notin);
	head = tail = LIST(node);
	while (accept(J, ',')) {
		node = vardec(J, notin);
		tail = tail->b = LIST(node);
	}
	return head;
}

static js_Ast *expopt(js_State *J, int end)
{
	js_Ast *a = NULL;
	if (J->lookahead != end)
		a = expression(J, 0);
	expect(J, end);
	return a;
}

static js_Ast *casestatementlist(js_State *J)
{
	js_Ast *head, *tail, *node;

	if (J->lookahead == '}' || J->lookahead == TK_CASE || J->lookahead == TK_DEFAULT)
		return NULL;

	node = statement(J);
	head = tail = LIST(node);
	while (J->lookahead != '}' && J->lookahead != TK_CASE && J->lookahead != TK_DEFAULT) {
		node = statement(J);
		tail = tail->b = LIST(node);
	}

	return head;
}

static js_Ast *caseclause(js_State *J)
{
	js_Ast *a, *b;

	if (accept(J, TK_CASE)) {
		a = expression(J, 0);
		expect(J, ':');
		b = casestatementlist(J);
		return STM2(CASE, a, b);
	}

	if (accept(J, TK_DEFAULT)) {
		expect(J, ':');
		a = casestatementlist(J);
		return STM1(DEFAULT, a);
	}

	jsP_error(J, "unexpected token in switch: %s", tokenstring[J->lookahead]);
	return NULL;
}

static js_Ast *caseblock(js_State *J)
{
	js_Ast *head, *tail, *node;

	expect(J, '{');
	if (accept(J, '}'))
		return STM1(BLOCK, NULL);

	node = caseclause(J);
	head = tail = LIST(node);
	while (J->lookahead != '}') {
		node = caseclause(J);
		tail = tail->b = LIST(node);
	}

	expect(J, '}');
	return STM1(BLOCK, head);
}

static js_Ast *block(js_State *J)
{
	js_Ast *head, *tail, *node;

	expect(J, '{');
	if (accept(J, '}'))
		return NULL;

	node = statement(J);
	head = tail = LIST(node);
	while (J->lookahead != '}') {
		node = statement(J);
		tail = tail->b = LIST(node);
	}

	expect(J, '}');
	return STM1(BLOCK, head);
}

static js_Ast *statement(js_State *J)
{
	js_Ast *a, *b, *c, *d;

	if (J->lookahead == '{') {
		return block(J);
	}

	if (accept(J, ';')) {
		return STM0(NOP);
	}

	if (accept(J, TK_CONTINUE)) {
		a = identifieropt(J);
		semicolon(J);
		return STM1(CONTINUE, a);
	}

	if (accept(J, TK_BREAK)) {
		a = identifieropt(J);
		semicolon(J);
		return STM1(BREAK, a);
	}

	if (accept(J, TK_RETURN)) {
		if (J->lookahead != ';' && J->lookahead != '}' && J->lookahead != 0)
			a = expression(J, 0);
		else
			a = NULL;
		semicolon(J);
		return STM1(RETURN, a);
	}

	if (accept(J, TK_WITH)) {
		expect(J, '(');
		a = expression(J, 0);
		expect(J, ')');
		b = statement(J);
		return STM2(WITH, a, b);
	}

	if (accept(J, TK_THROW)) {
		a = expression(J, 0);
		semicolon(J);
		return STM1(THROW, a);
	}

	if (accept(J, TK_TRY)) {
		a = block(J);
		b = c = d = NULL;
		if (accept(J, TK_CATCH)) {
			expect(J, '(');
			b = identifier(J);
			expect(J, ')');
			c = block(J);
		}
		if (accept(J, TK_FINALLY)) {
			d = block(J);
		}
		if (!b && !d)
			jsP_error(J, "unexpected token: %s (expected 'catch' or 'finally')", tokenstring[J->lookahead]);
		return STM4(TRY, a, b, c, d);
	}

	if (accept(J, TK_DEBUGGER)) {
		semicolon(J);
		return STM0(DEBUGGER);
	}

	if (accept(J, TK_IF)) {
		expect(J, '(');
		a = expression(J, 0);
		expect(J, ')');
		b = statement(J);
		if (accept(J, TK_ELSE))
			c = statement(J);
		else
			c = NULL;
		return STM3(IF, a, b, c);
	}

	if (accept(J, TK_DO)) {
		a = statement(J);
		expect(J, TK_WHILE);
		expect(J, '(');
		b = expression(J, 0);
		expect(J, ')');
		semicolon(J);
		return STM2(DO, a, b);
	}

	if (accept(J, TK_WHILE)) {
		expect(J, '(');
		a = expression(J, 0);
		expect(J, ')');
		b = statement(J);
		return STM2(WHILE, a, b);
	}

	if (accept(J, TK_VAR)) {
		a = vardeclist(J, 0);
		semicolon(J);
		return STM1(VAR, a);
	}

	if (accept(J, TK_FOR)) {
		expect(J, '(');
		if (accept(J, TK_VAR)) {
			a = vardeclist(J, 1);
			if (accept(J, ';')) {
				b = expopt(J, ';');
				c = expopt(J, ')');
				d = statement(J);
				return STM4(FOR_VAR, a, b, c, d);
			}
			if (accept(J, TK_IN)) {
				b = expression(J, 0);
				expect(J, ')');
				c = statement(J);
				return STM3(FOR_IN_VAR, a, b, c);
			}
			jsP_error(J, "unexpected token in for-var-statement: %s", tokenstring[J->lookahead]);
			return NULL;
		}

		if (J->lookahead != ';') {
			a = expression(J, 1);
		}
		if (accept(J, ';')) {
			b = expopt(J, ';');
			c = expopt(J, ')');
			d = statement(J);
			return STM4(FOR, a, b, c, d);
		}
		if (accept(J, TK_IN)) {
			b = expression(J, 0);
			expect(J, ')');
			c = statement(J);
			return STM3(FOR_IN, a, b, c);
		}
		jsP_error(J, "unexpected token in for-statement: %s", tokenstring[J->lookahead]);
		return NULL;
	}

	if (accept(J, TK_SWITCH)) {
		expect(J, '(');
		a = expression(J, 0);
		expect(J, ')');
		b = caseblock(J);
		return STM2(SWITCH, a, b);
	}

	/* LabelledStatement : Identifier ':' Statement */
	/* ExpressionStatement : Expression ';' */
	if (J->lookahead == TK_IDENTIFIER) {
		a = expression(J, 0);
		if (a->type == AST_IDENTIFIER && accept(J, ':')) {
			b = statement(J);
			return STM2(LABEL, a, b);
		}
		semicolon(J);
		return a;
	}

	/* ExpressionStatement : [lookahead not 'function' or '{'] Expression ';' */
	if (J->lookahead != TK_FUNCTION && J->lookahead != '{') {
		a = expression(J, 0);
		semicolon(J);
		return a;
	}

	jsP_error(J, "unexpected token in statement: %s", tokenstring[J->lookahead]);
	return NULL;
}

static js_Ast *fundec(js_State *J)
{
	js_Ast *a, *b, *c;
	a = identifier(J);
	expect(J, '(');
	b = paramlist(J);
	expect(J, ')');
	c = functionbody(J);
	return STM3(FUNC, a, b, c);
}

static js_Ast *sourceelement(js_State *J)
{
	if (accept(J, TK_FUNCTION))
		return fundec(J);
	return statement(J);
}

static js_Ast *sourcelist(js_State *J)
{
	js_Ast *head, *tail, *node;

	if (J->lookahead == '}' || J->lookahead == 0)
		return NULL;

	node = sourceelement(J);
	head = tail = LIST(node);
	while (J->lookahead != '}' && J->lookahead != 0) {
		node = sourceelement(J);
		tail = tail->b = LIST(node);
	}

	return STM1(BLOCK, head);
}

static js_Ast *functionbody(js_State *J)
{
	js_Ast *a;

	expect(J, '{');
	a = sourcelist(J);
	expect(J, '}');

	return a;
}

int jsP_error(js_State *J, const char *fmt, ...)
{
	va_list ap;

	fprintf(stderr, "syntax error: %s:%d: ", J->filename, J->line);

	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);

	fprintf(stderr, "\n");

	longjmp(J->jb, 1);
	return 0;
}

int jsP_parse(js_State *J, const char *filename, const char *source)
{
	jsP_initlex(J, filename, source);

	if (setjmp(J->jb)) {
		jsP_freeast(J);
		return 1;
	}

	next(J);
	printblock(sourcelist(J)->a, 0);
	putchar('\n');

	// TODO: compile to bytecode

	jsP_freeast(J);
	return 0;
}