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[as] Rewrite getargs()

Getargs() has not to do parsing anymore since this task is
done in expr() now.

--- a/as/as.h

+++ b/as/as.h

@@ -112,7 +112,7 @@

 #endif

 /* expr.c */

-extern Node *expr(char *s);

+extern Node *expr(char **s);

 extern void deltree(Node *np);

 /*

--- a/as/expr.c

+++ b/as/expr.c

@@ -175,8 +175,8 @@

 	int c;

 	char *p;

-	for (endp = textp+1; isalnum(c = *endp) || c == '_' || c == '.'; ++endp)

-		/* nothing */;

+	while (isalnum(c = *endp) || c == '_' || c == '.')

+		++endp;

 	tok2str();

 	yylval.sym = lookup(yytext);

@@ -189,8 +189,8 @@

 	int c;

 	char *p;

-	for (endp = textp+1; isxdigit(*endp); ++endp)

-		/* nothing */;

+	while (isxdigit(*endp))

+		++endp;

 	tok2str();

 	yylval.sym = tmpsym(atoi(yytext));  /* TODO: parse the string */

@@ -203,8 +203,8 @@

 	int c;

 	char *p;

-	for (endp = textp+1; *endp != '\''; ++endp)

-		/* nothing */;

+	while (*endp != '\'')

+		++endp;

 	return NUMBER;

 }

@@ -214,12 +214,27 @@

 	int c;

 	char *p;

-	for (endp = textp+1; *endp != '"'; ++endp)

-		/* nothing */;

+	while (*endp != '"')

+		++endp;

 	return STRING;

 }

 static int

+operator(void)

+{

+	int c;

+

+	++endp;

+	if ((c = *textp) == '>')

+		c = follow('=', '>', LE, SHL, '>');

+	else if (c == '<')

+		c = follow('=', '<', GE, SHR, '>');

+	tok2str();

+

+	return c;

+}

+

+static int

 next(void)

 {

 	int c;

@@ -226,19 +241,24 @@

 	while (isspace(*textp))

 		++textp;

-	c = *textp;

+

+	endp = textp;

+	if ((c = *textp) == '\0') {

+		strcpy(yytext, "EOF");

+		yylen = 3;

+		return EOF;

+	}

+

 	if (isalpha(c) || c == '_' || c == '.')

 		c = iden();

 	else if (isdigit(c))

 		c = number();

-	else if (c == '>')

-		c = follow('=', '>', LE, SHL, '>');

-	else if (c == '<')

-		c = follow('=', '<', GE, SHR, '>');

-	else if (c == '\'')

-		c = character();

 	else if (c == '\"')

 		c = string();

+	else if (c == '\'')

+		c = character();

+	else

+		c = operator();

 	return yytoken = c;

 }

@@ -398,15 +418,20 @@

 }

 Node *

-expr(char *s)

+expr(char **s)

 {

 	Node *np;

-	textp = s;

+	if (*s == '\0')

+		return NULL;

+

+	textp = *s;

 	next();

 	np = or();

-	if (*textp != '\0')

-		error("trailing characters in expression '%s'", textp);

+	if (yytoken != ',' && yytoken != EOF)

+		error("trailing characters in expression '%s:%s'", *s, textp);

+	*s = endp;

+

 	return np;

 }

--- a/as/parser.c

+++ b/as/parser.c

@@ -35,8 +35,6 @@

 Node **

 getargs(char *s)

 {

-	char *t;

-	int ch, len;

 	Node **ap;

 	static Node *args[NARGS];

@@ -43,25 +41,11 @@

 	if (!s)

 		return NULL;

-	for (ap = args; ; *ap++ = expr(t)) {

-		while (isspace(*s))

-			++s;

-		if (*s == '\0')

-			break;

-		if (ap == &args[NARGS-1])

-			error("too many arguments in one instruction");

-

-		for (t = s; *s && *s != ','; s++)

-			/* nothing */;

-		len = t - s;

-		if (*s != '\0')

-			*s++ = '\0';

-		if (len == 0)

-			error("wrong operand '%s'", t);

+	for (ap = args; ap < &args[NARGS-1]; ++ap) {

+		if ((*ap = expr(&s)) == NULL)

+			return args;

 	}

-	*ap = NULL;

-

-	return args;

+	error("too many arguments in one instruction");

 }

 static char *