// Returns the next token in the character stream.
// If no next token can be identified, an error
// is emitted and we return the error token.
Token
Lexer::scan()
{
// Consume any white space here.
space();
switch (peek()) {
case 0: return eof();
case '(': return lparen();
case ')': return rparen();
case '-':
if (peek(1) == '>')
return arrow();
else
return error();
default:
if (Token tok = identifier())
return tok;
else
return error();
}
}
static void do_stmt(void) {
int ls, lb, lc;
Token = scan();
ls = label();
pushbrk(lb = label());
pushcont(lc = label());
genlab(ls);
stmt();
match(WHILE, "'while'");
lparen();
genlab(lc);
rexpr();
genbrtrue(ls);
genlab(lb);
rparen();
semi();
Bsp--;
Csp--;
}
static void if_stmt(void) {
int l1, l2;
Token = scan();
lparen();
rexpr();
clear();
rparen();
l1 = label();
genbrfalse(l1);
stmt();
if (ELSE == Token) {
l2 = label();
genjump(l2);
genlab(l1);
l1 = l2;
Token = scan();
stmt();
}
genlab(l1);
}
static void for_stmt(void) {
int ls, lbody, lb, lc;
Token = scan();
ls = label();
lbody = label();
pushbrk(lb = label());
pushcont(lc = label());
lparen();
if (Token != SEMI) {
rexpr();
clear();
}
semi();
genlab(ls);
if (Token != SEMI) {
rexpr();
clear();
genbrfalse(lb);
}
genjump(lbody);
semi();
genlab(lc);
if (Token != RPAREN) {
rexpr();
clear();
}
genjump(ls);
rparen();
genlab(lbody);
stmt();
genjump(lc);
genlab(lb);
Bsp--;
Csp--;
}
// Returns the next token in the character stream.
// If no next token can be identified, an error
// is emitted and we return the error token.
Token
Lexer::scan()
{
// Keep consuming characters until we find
// a token.
while (true) {
space();
// Update the position of the current source location.
// This denotes the beginning of the current token.
loc_ = in_.location();
switch (peek()) {
case 0: return eof();
case '{': return lbrace();
case '}': return rbrace();
case '(': return lparen();
case ')': return rparen();
case '[': return lbrack();
case ']': return rbrack();
case ',': return comma();
case ':': return colon();
case ';': return semicolon();
case '.': return dot();
case '+': return plus();
case '-': return minus();
case '*': return star();
case '/':
get();
if (peek() == '/') {
comment();
continue;
} else {
return slash();
}
case '%': return percent();
case '=': return equal();
case '!': return bang();
case '<': return langle();
case '>': return rangle();
case '&': return ampersand();
case '|': return bar();
case '^': return hat();
case '0':
// if the next character is a 'b' then this
// is a binary literal
if (peek(1) == 'b')
return binary_integer();
// if the next character is an 'x' then this
// is a hexadecimal integer
if (peek(1) == 'x')
return hexadecimal_integer();
// otherwise proceed to regular integer lexing
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
return integer();
case 'a': case 'b': case 'c': case 'd': case 'e':
case 'f': case 'g': case 'h': case 'i': case 'j':
case 'k': case 'l': case 'm': case 'n': case 'o':
case 'p': case 'q': case 'r': case 's': case 't':
case 'u': case 'v': case 'w': case 'x': case 'y':
case 'z':
case 'A': case 'B': case 'C': case 'D': case 'E':
case 'F': case 'G': case 'H': case 'I': case 'J':
case 'K': case 'L': case 'M': case 'N': case 'O':
case 'P': case 'Q': case 'R': case 'S': case 'T':
case 'U': case 'V': case 'W': case 'X': case 'Y':
case 'Z':
case '_':
return word();
case '\'': return character();
case '"': return string();
default:
return error();
}
}
}
static void act15()
{
NLA = ENTRY_OPEN;
lparen ();
}
