refactor(parser): Move keyword_ignoring to keyword module

The subtle detail in the implementation is that keyword_ignoring will now _not_ bypass the any_token parser. As such, it does not take a shortcut, but also the keyword is technically read into memory, and later discarded for convenience (not for memory micro-optimization).

Author: ngeor

rusty_parser/src/built_ins/open.rs

@@ -4,7 +4,7 @@ use rusty_pc::*;
 
 use crate::input::StringView;
 use crate::pc_specific::*;
-use crate::tokens::{equal_sign_ws, keyword_ignoring, whitespace_ignoring};
+use crate::tokens::{equal_sign_ws, whitespace_ignoring};
 use crate::{BuiltInSub, ParserError, *};
 pub fn parse() -> impl Parser<StringView, Output = Statement, Error = ParserError> {
     seq6(

rusty_parser/src/core/resume.rs

@@ -4,7 +4,7 @@ use crate::core::name::bare_name_p;
 use crate::core::statement_separator::peek_eof_or_statement_separator;
 use crate::input::StringView;
 use crate::pc_specific::*;
-use crate::tokens::{keyword_ignoring, whitespace_ignoring};
+use crate::tokens::whitespace_ignoring;
 use crate::{Keyword, ParserError, ResumeOption, Statement};
 
 // RESUME

rusty_parser/src/core/select_case.rs

@@ -6,7 +6,7 @@ use crate::core::statement_separator::comments_in_between_keywords;
 use crate::core::statements::zero_or_more_statements;
 use crate::input::StringView;
 use crate::pc_specific::*;
-use crate::tokens::{keyword_ignoring, whitespace_ignoring};
+use crate::tokens::whitespace_ignoring;
 use crate::{ParserError, *};
 
 // SELECT CASE expr ' comment
@@ -115,7 +115,7 @@ mod case_expression_parser {
     use crate::core::opt_second_expression::opt_second_expression_after_keyword;
     use crate::input::StringView;
     use crate::pc_specific::*;
-    use crate::tokens::{TokenType, any_token, keyword_ignoring, whitespace_ignoring};
+    use crate::tokens::{TokenType, any_token, whitespace_ignoring};
     use crate::{CaseExpression, ExpressionTrait, Keyword, Operator, ParserError};
 
     pub fn parser() -> impl Parser<StringView, Output = CaseExpression, Error = ParserError> {

rusty_parser/src/core/statement.rs

@@ -392,7 +392,7 @@ mod system {
     use crate::core::statement_separator::peek_eof_or_statement_separator;
     use crate::input::StringView;
     use crate::pc_specific::*;
-    use crate::tokens::{keyword_ignoring, whitespace_ignoring};
+    use crate::tokens::whitespace_ignoring;
     use crate::{Keyword, ParserError, Statement};
 
     pub fn parse_system_p() -> impl Parser<StringView, Output = Statement, Error = ParserError> {

rusty_parser/src/core/var_name.rs

@@ -4,7 +4,7 @@ use rusty_pc::*;
 use crate::core::name::{bare_name_without_dots, name_p};
 use crate::input::StringView;
 use crate::pc_specific::*;
-use crate::tokens::{keyword_ignoring, whitespace_ignoring};
+use crate::tokens::whitespace_ignoring;
 use crate::{ParserError, *};
 
 /// A variable name with a type.

rusty_parser/src/pc_specific/keyword.rs

@@ -4,7 +4,8 @@ use rusty_pc::and::IgnoringBothCombiner;
 use rusty_pc::*;
 
 use crate::input::StringView;
-use crate::tokens::{TokenType, any_token, keyword_ignoring, whitespace_ignoring};
+use crate::pc_specific::WithExpected;
+use crate::tokens::{TokenMatcher, TokenType, any_token, whitespace_ignoring};
 use crate::{Keyword, ParserError};
 
 // TODO review usages of TokenType::Keyword
@@ -38,6 +39,13 @@ pub fn keyword_p(
     KeywordParser::new(any_token(), keywords, eof_is_fatal)
 }
 
+pub fn keyword_ignoring(k: Keyword) -> impl Parser<StringView, Output = (), Error = ParserError> {
+    any_token()
+        .filter(move |t| k.matches_token(t))
+        .map_to_unit()
+        .with_expected_message(format!("Expected: {}", k))
+}
+
 /// Parses the given keyword, followed by mandatory whitespace.
 pub fn keyword_ws_p(k: Keyword) -> impl Parser<StringView, Output = (), Error = ParserError> {
     keyword_ignoring(k).and(whitespace_ignoring().to_fatal(), IgnoringBothCombiner)

rusty_parser/src/tokens/any_token.rs

@@ -5,8 +5,8 @@ use rusty_pc::*;
 
 use crate::input::StringView;
 use crate::pc_specific::WithExpected;
+use crate::tokens::TokenType;
 use crate::tokens::any_symbol::any_symbol;
-use crate::tokens::{TokenMatcher, TokenType};
 use crate::{Keyword, ParserError};
 
 /// Parses any token.
@@ -133,13 +133,6 @@ fn any_keyword() -> impl Parser<StringView, Output = Token, Error = ParserError>
         .to_token(TokenType::Keyword)
 }
 
-pub fn keyword_ignoring(k: Keyword) -> impl Parser<StringView, Output = (), Error = ParserError> {
-    any_token()
-        .filter(move |t| k.matches_token(t))
-        .map_to_unit()
-        .with_expected_message(format!("Expected: {}", k))
-}
-
 fn ensure_no_illegal_char_after_keyword()
 -> impl Parser<StringView, Output = (), Error = ParserError> {
     peek_p().to_option().and_then(|opt_ch| match opt_ch {