int statement(ParserState* ps) {
Ast *start = ps->curr, *expr = 0;
if (stepifis(ps, PSemi)) { parwrn(ps, "empty statement"); }
else if (stepifis(ps, RBreak)) {
if (stepifis(ps, PSemi)) {}
else { parerr(ps, "expecting ';' after break"); }
}
else if (stepifis(ps, RReturn)) {
if (expression(ps, &expr)) {
ast_next_to_first_child(start);
}
if (stepifis(ps, PSemi)) {}
else { parerr(ps, "expecting ';'"); }
}
else if (if_statement(ps)) {}
else if (while_statement(ps)) {}
else if (variable_decl(ps)) {}
else if (statement_block(ps)) {}
else if (expression(ps, &expr)) {
Ast* lhs = expr;
Ast* op = ps->curr;
if (curris(ps, OpAsgn)) {
step(ps);
if (expression(ps, &expr)) {
if (lhs->t == AstGetIdx || lhs->t == AstGetKey) {
lhs->t++;
free(ast_rmnext(lhs));
ast_next_to_last_child(lhs);
}
else {
ast_swap(lhs, op);
ast_next_to_first_child(lhs);
ast_next_to_last_child(lhs);
}
}
else {
parerr(ps, "invalid assignment");
}
}
else if (stepifis(ps, OpInc) || stepifis(ps, OpDec)) {
ast_swap(lhs, op);
ast_next_to_first_child(lhs);
}
if (stepifis(ps, PSemi)) {}
else {
parerr(ps, "invalid syntax, missing ';'?");
}
}
else return 0;
return 1;
}
int compilation_unit(ParserState* ps) {
while (ps->curr != 0) {
if (function_decl(ps)) {}
else if (variable_decl(ps)) {}
else if (statement(ps)) {}
else break;
}
if (ps->curr != 0) {
parerr(ps, "invalid syntax");
}
return 1;
}
// Parse a declaration.
//
// decl -> [specifier-seq] entity-decl
//
// entity-decl -> variable-decl
// | function-decl
Decl*
Parser::decl()
{
// optional specifier-seq
Specifier spec = specifier_seq();
// entity-decl
switch (lookahead()) {
case var_kw:
return variable_decl(spec);
case def_kw:
return function_decl(spec);
case struct_kw:
return record_decl(spec);
default:
// TODO: Is this a recoverable error?
error("invalid declaration");
}
}
