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daisy
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Added recursive parsing 

Improved error handling
pull/2/head
Mark 2023-03-23 14:53:27 -07:00
parent 850682b42f
commit 4c8a916085
Signed by: Mark
GPG Key ID: AD62BB059C2AAEE4
1 changed files with 29 additions and 5 deletions
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34
src/parser/treeify.rs
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@ -39,11 +39,20 @@ fn treeify_binary(
) -> Result<usize, (LineLocation, ParserError)> { ) -> Result<usize, (LineLocation, ParserError)> {
let this: &Token = &g_inner[i]; let this: &Token = &g_inner[i];
if i == 0 {
// This binary operator is at the end of an expression.
let l = match this {
Token::PreOperator(l, _) => l,
_ => panic!()
};
return Err((*l, ParserError::Syntax));
}
let right: &Token = { let right: &Token = {
if i < g_inner.len()-1 { if i < g_inner.len()-1 {
&g_inner[i+1] &g_inner[i+1]
} else { } else {
// This binary operator is at the end of the expression.
let l = match this { let l = match this {
Token::PreOperator(l, _) => l, Token::PreOperator(l, _) => l,
_ => panic!() _ => panic!()
@ -102,9 +111,11 @@ fn treeify_binary(
if right_val.is_none() || this_val > right_val.unwrap() { if right_val.is_none() || this_val > right_val.unwrap() {
// This operator has higher precedence, it takes both arguments // This operator has higher precedence, it takes both arguments
let left = g_inner.remove(i-1).unwrap(); let mut left = g_inner.remove(i-1).unwrap();
let this = g_inner.remove(i-1).unwrap(); let this = g_inner.remove(i-1).unwrap();
let right = g_inner.remove(i-1).unwrap(); let mut right = g_inner.remove(i-1).unwrap();
if let Token::PreGroup(_, _) = right { treeify(&mut right)?; }
if let Token::PreGroup(_, _) = left { treeify(&mut left)?; }
let k = match this { let k = match this {
Token::PreOperator(_, k) => k, Token::PreOperator(_, k) => k,
@ -197,7 +208,8 @@ fn treeify_unaryleft(
if right_val.is_none() || this_val > right_val.unwrap() { if right_val.is_none() || this_val > right_val.unwrap() {
let this = g_inner.remove(i).unwrap(); let this = g_inner.remove(i).unwrap();
let right = g_inner.remove(i).unwrap(); let mut right = g_inner.remove(i).unwrap();
if let Token::PreGroup(_, _) = right { treeify(&mut right)?; }
let k = match this { let k = match this {
Token::PreOperator(_, k) => k, Token::PreOperator(_, k) => k,
@ -296,7 +308,8 @@ fn treeify_unaryright(
if left_val.is_none() || this_val > left_val.unwrap() { if left_val.is_none() || this_val > left_val.unwrap() {
let this = g_inner.remove(i).unwrap(); let this = g_inner.remove(i).unwrap();
let left = g_inner.remove(i-1).unwrap(); let mut left = g_inner.remove(i-1).unwrap();
if let Token::PreGroup(_, _) = left { treeify(&mut left)?; }
let k = match this { let k = match this {
Token::PreOperator(_, k) => k, Token::PreOperator(_, k) => k,
@ -355,5 +368,16 @@ pub fn treeify(
}; };
} }
*g = g_inner.pop_front().unwrap();
// Catch the edge case where the entire group we're given
// consists of one operator. This is always a syntax error.
match g {
Token::PreOperator(l, _) => {
return Err((*l, ParserError::Syntax));
},
_ => {}
};
return Ok(()); return Ok(());
} }