// Parse a function declarator.
// fn-decl ::= n(p1, p2, ...) -> t
Tree*
parse_fn_decl(Parser& p, Tree* n) {
if (Tree_seq* ps = parse_parm_clause(p))
//parsing parameter list as Lambda abstraction \(pi:Ti).e
if (Tree* t = parse_return_type(p))
return new Func_tree(n, ps, t);
return nullptr;
}
// Parse a lambda abstraction.
//
// lambda-expr ::= '\' parm-decl ':' type '=>' term
// | '\' parm-list '=>' term
Tree*
parse_lambda_expr(Parser& p) {
if (const Token* k = parse::accept(p, backslash_tok)) {
if(Tree* v = parse_parm_decl(p)) {
if (parse::expect(p, map_tok)) {
if (Tree* t = parse_expr(p))
return new Abs_tree(k, v, t);
else
parse::parse_error(p) << "expected 'expr' after '.'";
}
} else if (Tree_seq* ps = parse_parm_clause(p)) {
if (parse::expect(p, map_tok)) {
if (Tree* t = parse_expr(p))
return new Fn_tree(k, ps, t);
else
parse::parse_error(p) << "expected 'expr' after '.'";
}
} else {
parse::parse_error(p) << "expected 'var-decl' or 'parm-clause' after '\\'";
}
}
return nullptr;
}