refactor(parser): Use peek_token() to streamline peek operations

[surajk-m]

Closes #830

This PR refactors parser to use peek_token() instead of separate peek() and peek_data() calls.

Changes:

• Replaced instances of peek() / peek_data() call pairs.
• Removed unwrap() by working directly with the peek_token(). This ensures that the token's kind and data are always in sync and that no intermediate changes can occur between the checks.

[apollo-cla]

@surajk-m: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Apollo Contributor License Agreement here: https://contribute.apollographql.com/

[SimonSapin]

Hi, and thanks for submitting this PR!

Issue #830 specifically pertains to the pattern where peek() is followed by peek_data().unwrap(), it’s the unwrap() part and its potential panic that we try to avoid. Using peek() or peek_data() without unwrap() is fine and should not be replaced with more verbose code.

There are a few other locations with the peek_data().unwrap() pattern is used:

• crates/apollo-parser/src/parser/grammar/fragment.rs
• crates/apollo-parser/src/parser/grammar/document.rs
• crates/apollo-parser/src/parser/grammar/value.rs
• crates/apollo-parser/src/parser/grammar/name.rs

Would you be able to update those locations as well and undo the cases where peek_token() isn't needed?

[surajk-m]

Hi @SimonSapin,

Thanks for reviewing my PR! I'll revert the changes where peek_token() isn't needed and will update the remaining instances of peek_data().unwrap() pattern used in the mentioned files.