Add data_push parameter to DataStack::reduce_action
#41
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Summary of ChangesHello @ehwan, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed! This pull request introduces a Highlights
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Code Review
This pull request introduces a push_data parameter to the DataStack::reduce_action method, which is a nice refactoring. It makes the intent clearer and moves the logic of whether to push data into the DataStack implementation, simplifying the parser context code in both deterministic and non-deterministic parsers. The changes are well-propagated through the codebase, including the code generator and example files. I have one suggestion to improve the maintainability of the code generator.
| if rule.tokens.len() > 0 { | ||
| // if first token's tag is equal to new_tag, no need to (pop n tokens -> push new token). | ||
| // just pop n-1 tokens | ||
| let first_tag_name = token_to_stack_name(rule.tokens[0].token) | ||
| .unwrap_or(&empty_tag_name); | ||
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|
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| if first_tag_name == new_tag_name { | ||
| // pop n-1 tokens, no new insertion | ||
| let len = rule.tokens.len() - 1; | ||
| let truncate_stream = if len > 0 { | ||
| quote! {__data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #len);} | ||
| if new_tag_name == &empty_tag_name { | ||
| // if first token's tag is equal to new_tag, no need to (pop n tokens -> push new token). | ||
| // just pop n-1 tokens | ||
| let first_tag_name = token_to_stack_name(rule.tokens[0].token) | ||
| .unwrap_or(&empty_tag_name); | ||
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| if first_tag_name == new_tag_name { | ||
| // pop n-1 tokens, no new insertion | ||
| let len = rule.tokens.len() - 1; | ||
| let truncate_stream = if len > 0 { | ||
| quote! {__data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #len);} | ||
| } else { | ||
| TokenStream::new() | ||
| }; | ||
| truncate_stream | ||
| } else { | ||
| TokenStream::new() | ||
| }; | ||
| truncate_stream | ||
| let len = rule.tokens.len(); | ||
| // len > 0 here | ||
| quote! { | ||
| __data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #len); | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name); | ||
| } | ||
| } | ||
| } else { | ||
| let len = rule.tokens.len(); | ||
| // len > 0 here | ||
| quote! { | ||
| __data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #len); | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name); | ||
| // if first token's tag is equal to new_tag, no need to (pop n tokens -> push new token). | ||
| // just pop n-1 tokens | ||
| let first_tag_name = token_to_stack_name(rule.tokens[0].token) | ||
| .unwrap_or(&empty_tag_name); | ||
|
|
||
| if first_tag_name == new_tag_name { | ||
| // pop n-1 tokens, no new insertion | ||
| let lenm1 = rule.tokens.len() - 1; | ||
| let truncate_stream = if lenm1 > 0 { | ||
| quote! {__data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #lenm1);} | ||
| } else { | ||
| TokenStream::new() | ||
| }; | ||
|
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||
| let len = rule.tokens.len(); | ||
| quote! { | ||
| if __push_data { | ||
| #truncate_stream | ||
| } else { | ||
| __data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #len); | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#empty_tag_name); | ||
| } | ||
| } | ||
| } else if first_tag_name == &empty_tag_name { | ||
| // pop n-1 tokens, no new insertion | ||
| let lenm1 = rule.tokens.len() - 1; | ||
| let truncate_stream = if lenm1 > 0 { | ||
| quote! {__data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #lenm1);} | ||
| } else { | ||
| TokenStream::new() | ||
| }; | ||
|
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||
| let len = rule.tokens.len(); | ||
| quote! { | ||
| if __push_data { | ||
| __data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #len); | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name); | ||
| } else { | ||
| #truncate_stream | ||
| } | ||
| } | ||
| } else { | ||
| let len = rule.tokens.len(); | ||
| // len > 0 here | ||
| quote! { | ||
| __data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #len); | ||
| if __push_data { | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name); | ||
| } else { | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#empty_tag_name); | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } else { | ||
| quote! { | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name); | ||
| if new_tag_name == &empty_tag_name { | ||
| quote! { | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name); | ||
| } | ||
| } else { | ||
| quote! { | ||
| if __push_data { | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name); | ||
| } else { | ||
| __data_stack.#tag_stack_name.push(#tag_enum_name::#empty_tag_name); | ||
| } | ||
| } | ||
| } | ||
| } |
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The logic for generating tag stack modifications is quite complex and contains a lot of duplicated code. This makes it hard to read and maintain. For example, let first_tag_name = ... and the logic to create truncate_stream are repeated.
Consider refactoring this block to reduce duplication. You could extract common variables and structures to the top of the if rule.tokens.len() > 0 block. This would make the logic for each case clearer and the whole block more maintainable.
This refactoring would also help avoid generating code like if __push_data {} else { ... } which is functionally correct but stylistically awkward.
if rule.tokens.len() > 0 {
let first_tag_name = token_to_stack_name(rule.tokens[0].token)
.unwrap_or(&empty_tag_name);
let len = rule.tokens.len();
let lenm1 = len - 1;
let truncate_lenm1 = if lenm1 > 0 {
quote! {__data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #lenm1);}
} else {
TokenStream::new()
};
let truncate_len = quote! {__data_stack.#tag_stack_name.truncate(__data_stack.#tag_stack_name.len() - #len);};
if new_tag_name == &empty_tag_name {
if first_tag_name == new_tag_name {
// pop n-1 tokens, no new insertion
truncate_lenm1
} else {
// pop n tokens, push empty
quote! {
#truncate_len
__data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name);
}
}
} else { // new_tag_name is not empty
if first_tag_name == new_tag_name {
// pop n-1 tokens if __push_data, else pop n and push empty
quote! {
if __push_data {
#truncate_lenm1
} else {
#truncate_len
__data_stack.#tag_stack_name.push(#tag_enum_name::#empty_tag_name);
}
}
} else if first_tag_name == &empty_tag_name {
// pop n and push new if __push_data, else pop n-1
quote! {
if __push_data {
#truncate_len
__data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name);
} else {
#truncate_lenm1
}
}
} else {
// pop n, and push new or empty based on __push_data
quote! {
#truncate_len
if __push_data {
__data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name);
} else {
__data_stack.#tag_stack_name.push(#tag_enum_name::#empty_tag_name);
}
}
}
}
} else {
if new_tag_name == &empty_tag_name {
quote! {
__data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name);
}
} else {
quote! {
if __push_data {
__data_stack.#tag_stack_name.push(#tag_enum_name::#new_tag_name);
} else {
__data_stack.#tag_stack_name.push(#tag_enum_name::#empty_tag_name);
}
}
}
}
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