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Nasal-Interpreter
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✨ fix old ambiguous syntax

This commit is contained in:
ValKmjolnir 2023-08-20 22:35:24 +08:00
parent 98b0086656
commit 6f259dc1ea
2 changed files with 46 additions and 27 deletions
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68
src/nasal_parse.cpp
View File

@ -13,7 +13,7 @@ const error& parse::compile(const lexer& lexer) {
match(tok::semi);
} else if (need_semi_check(root->get_expressions().back()) && !lookahead(tok::eof)) {
// the last expression can be recognized without semi
die(prevspan, "expected \";\"");
die(prevspan, "expected \";\" after this token");
}
}
update_location(root);
@ -60,6 +60,13 @@ void parse::die(const span& loc, std::string info) {
err.err("parse", loc, info);
}
void parse::next() {
if (lookahead(tok::eof)) {
return;
}
++ptr;
}
void parse::match(tok type, const char* info) {
if (!lookahead(type)) {
if (info) {
@ -70,13 +77,10 @@ void parse::match(tok type, const char* info) {
case tok::num:die(thisspan, "expected number"); break;
case tok::str:die(thisspan, "expected string"); break;
case tok::id: die(thisspan, "expected identifier");break;
default: die(thisspan, "expected '"+tokname.at(type)+"'"); break;
default: die(thisspan, "expected \""+tokname.at(type)+"\""); break;
}
return;
}
if (lookahead(tok::eof)) {
return;
}
next();
}
@ -91,7 +95,7 @@ bool parse::is_call(tok type) {
bool parse::check_comma(const tok* panic_set) {
for(u32 i=0;panic_set[i]!=tok::null;++i) {
if (lookahead(panic_set[i])) {
die(prevspan, "expected ',' between scalars");
die(prevspan, "expected \",\" between scalars");
return true;
}
}
@ -133,9 +137,21 @@ bool parse::check_func_end(expr* node) {
return false;
}
bool parse::check_in_curve_multi_definition() {
// we do not allow syntax like:
// func {}(var a, b, c)
// but we still allow syntax like:
// func {}(var a = 1)
// in fact, this syntax is not recommended
if (!lookahead(tok::lcurve) || toks[ptr+1].type!=tok::var) {
return false;
}
return toks[ptr+2].type==tok::id && toks[ptr+3].type==tok::comma;
}
bool parse::check_special_call() {
// special call means like this: function_name(a:1,b:2,c:3);
u32 check_ptr=ptr, curve=1, bracket=0, brace=0;
u32 check_ptr = ptr, curve = 1, bracket = 0, brace = 0;
while(toks[++check_ptr].type!=tok::eof && curve) {
switch(toks[check_ptr].type) {
case tok::lcurve: ++curve; break;
@ -236,7 +252,7 @@ vector_expr* parse::vec() {
}
}
update_location(node);
match(tok::rbracket, "expected ']' when generating vector");
match(tok::rbracket, "expected \"]\" when generating vector");
return node;
}
@ -248,13 +264,13 @@ hash_expr* parse::hash() {
if (lookahead(tok::comma)) {
match(tok::comma);
} else if (lookahead(tok::id) || lookahead(tok::str)) { // first set of hashmember
die(prevspan, "expected ',' between hash members");
die(prevspan, "expected \",\" between hash members");
} else {
break;
}
}
update_location(node);
match(tok::rbrace, "expected '}' when generating hash");
match(tok::rbrace, "expected \"}\" when generating hash");
return node;
}
@ -309,13 +325,13 @@ void parse::params(function* func_node) {
if (lookahead(tok::comma)) {
match(tok::comma);
} else if (lookahead(tok::id)) { // first set of identifier
die(prevspan, "expected ',' between identifiers");
die(prevspan, "expected \",\" between identifiers");
} else {
break;
}
}
update_location(func_node);
match(tok::rcurve, "expected ')' after parameter list");
match(tok::rcurve, "expected \")\" after parameter list");
return;
}
@ -381,10 +397,10 @@ code_block* parse::expression_block() {
match(tok::semi);
} else if (need_semi_check(node->get_expressions().back()) && !lookahead(tok::rbrace)) {
// the last expression can be recognized without semi
die(prevspan, "expected ';'");
die(prevspan, "expected \";\" after this token");
}
}
match(tok::rbrace, "expected '}' when generating expressions");
match(tok::rbrace, "expected \"}\" when generating expressions");
} else {
node->add_expression(expression());
if (lookahead(tok::semi)) {
@ -634,10 +650,12 @@ expr* parse::scalar() {
die(thisspan, "expected scalar");
return null();
}
// check call and avoid ambiguous syntax
// i don't know why using `&& !(lookahead(tok::lcurve) && toks[ptr+1].type==tok::var)`
// here, maybe we'll find the reason XD
if (is_call(toks[ptr].type)) {
// check call and avoid ambiguous syntax:
// var f = func(){}
// (var a, b, c) = (1, 2, 3);
// will be incorrectly recognized like:
// var f = func(){}(var a, b, c)
if (is_call(toks[ptr].type) && !check_in_curve_multi_definition()) {
auto call_node = new call_expr(toks[ptr].loc);
call_node->set_first(node);
while(is_call(toks[ptr].type)) {
@ -695,7 +713,7 @@ call_vector* parse::callv() {
die(thisspan, "expected index value");
}
update_location(node);
match(tok::rbracket, "expected ']' when calling vector");
match(tok::rbracket, "expected \"]\" when calling vector");
return node;
}
@ -722,7 +740,7 @@ call_function* parse::callf() {
break;
}
update_location(node);
match(tok::rcurve, "expected ')' when calling function");
match(tok::rcurve, "expected \")\" when calling function");
return node;
}
@ -790,7 +808,7 @@ multi_identifier* parse::multi_id() {
if (lookahead(tok::comma)) {
match(tok::comma);
} else if (lookahead(tok::id)) { // first set of identifier
die(prevspan, "expected ',' between identifiers");
die(prevspan, "expected \",\" between identifiers");
} else {
break;
}
@ -820,7 +838,7 @@ tuple_expr* parse::multi_scalar() {
}
}
update_location(node);
match(tok::rcurve, "expected ')' after multi-scalar");
match(tok::rcurve, "expected \")\" after multi-scalar");
return node;
}
@ -887,7 +905,7 @@ for_expr* parse::for_loop() {
} else {
node->set_initial(calc());
}
match(tok::semi, "expected ';' in for(;;)");
match(tok::semi, "expected \";\" in for(;;)");
// conditional expression
if (lookahead(tok::eof)) {
@ -898,7 +916,7 @@ for_expr* parse::for_loop() {
} else {
node->set_condition(calc());
}
match(tok::semi, "expected ';' in for(;;)");
match(tok::semi, "expected \";\" in for(;;)");
//after loop expression
if (lookahead(tok::eof)) {
@ -935,7 +953,7 @@ forei_expr* parse::forei_loop() {
die(thisspan, "expected iterator");
}
node->set_iterator(iter_gen());
match(tok::semi, "expected ';' in foreach/forindex(iter;vector)");
match(tok::semi, "expected \";\" in foreach/forindex(iter;vector)");
if (lookahead(tok::eof)) {
die(thisspan, "expected vector");
}

5
src/nasal_parse.h
View File

@ -77,13 +77,14 @@ private:
private:
void die(const span&,std::string);
void next() {++ptr;}
void match(tok type, const char* info=nullptr);
void next();
void match(tok, const char* info=nullptr);
bool lookahead(tok);
bool is_call(tok);
bool check_comma(const tok*);
bool check_tuple();
bool check_func_end(expr*);
bool check_in_curve_multi_definition();
bool check_special_call();
bool need_semi_check(expr*);
void update_location(expr*);