From 2badb82be5c2164b65624c8f9f3c6a21c9a9a137 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@cs.stanford.edu>
Date: Mon, 26 Aug 2024 08:45:36 -0700
Subject: [PATCH] work

---
 rust/pspp/src/command.rs   | 14 +++++++-------
 rust/pspp/src/engine.rs    |  4 ++--
 rust/pspp/src/lex/lexer.rs | 26 ++++++--------------------
 3 files changed, 15 insertions(+), 29 deletions(-)

diff --git a/rust/pspp/src/command.rs b/rust/pspp/src/command.rs
index dfa8c5c68e..57bb885f14 100644
--- a/rust/pspp/src/command.rs
+++ b/rust/pspp/src/command.rs
@@ -7,7 +7,7 @@ use crate::{
     integer::ToInteger,
     lex::{
         command_name::CommandMatcher,
-        lexer::{NewLexer},
+        lexer::{TokenSlice},
         token::{Punct, Token},
     },
     message::Diagnostic,
@@ -126,7 +126,7 @@ fn commands() -> &'static [Command] {
     COMMANDS.get_or_init(|| new_commands()).as_slice()
 }
 
-fn parse_command_word(lexer: &mut NewLexer, s: &mut String, n: usize) -> bool {
+fn parse_command_word(lexer: &mut TokenSlice, s: &mut String, n: usize) -> bool {
     let separator = match s.chars().next_back() {
         Some(c) if c != '-' => " ",
         _ => "",
@@ -162,7 +162,7 @@ fn find_best_match(s: &str) -> (Option<&'static Command>, isize) {
 }
 
 fn parse_command_name(
-    lexer: &mut NewLexer,
+    lexer: &mut TokenSlice,
     error: &Box<dyn Fn(Diagnostic)>,
 ) -> Result<(&'static Command, usize), ()> {
     let mut s = String::new();
@@ -215,7 +215,7 @@ pub fn end_of_command(context: &Context, range: RangeFrom<usize>) -> Result<Succ
     }
 }
 
-fn parse_in_state(mut lexer: NewLexer, error: &Box<dyn Fn(Diagnostic)>, _state: State) {
+fn parse_in_state(mut lexer: TokenSlice, error: &Box<dyn Fn(Diagnostic)>, _state: State) {
     println!("{}:{}", file!(), line!());
     match lexer.get(0) {
         None | Some(Token::EndCommand) => (),
@@ -223,7 +223,7 @@ fn parse_in_state(mut lexer: NewLexer, error: &Box<dyn Fn(Diagnostic)>, _state:
             if let Ok((command, n_tokens)) = parse_command_name(&mut lexer, error) {
                 let mut context = Context {
                     error,
-                    lexer: lexer.sublexer(n_tokens..),
+                    lexer: lexer.subslice(n_tokens..),
                     command_name: Some(command.name),
                 };
                 (command.run)(&mut context);
@@ -232,13 +232,13 @@ fn parse_in_state(mut lexer: NewLexer, error: &Box<dyn Fn(Diagnostic)>, _state:
     }
 }
 
-pub fn parse_command(lexer: NewLexer, error: &Box<dyn Fn(Diagnostic)>) {
+pub fn parse_command(lexer: TokenSlice, error: &Box<dyn Fn(Diagnostic)>) {
     parse_in_state(lexer, error, State::Initial)
 }
 
 pub struct Context<'a> {
     error: &'a Box<dyn Fn(Diagnostic)>,
-    lexer: NewLexer<'a>,
+    lexer: TokenSlice<'a>,
     command_name: Option<&'static str>,
 }
 
diff --git a/rust/pspp/src/engine.rs b/rust/pspp/src/engine.rs
index 59021a184e..abfc2da8b3 100644
--- a/rust/pspp/src/engine.rs
+++ b/rust/pspp/src/engine.rs
@@ -1,7 +1,7 @@
 use crate::{
     command::parse_command,
     lex::{
-        lexer::{NewLexer, NewSource},
+        lexer::{TokenSlice, NewSource},
     },
     macros::MacroSet,
     message::Diagnostic,
@@ -19,7 +19,7 @@ impl Engine {
             let error: Box<dyn Fn(Diagnostic)> = Box::new(|diagnostic| {
                 println!("{diagnostic}");
             });
-            parse_command(NewLexer::new(&tokens), &error);
+            parse_command(TokenSlice::new(&tokens), &error);
         }
     }
 }
diff --git a/rust/pspp/src/lex/lexer.rs b/rust/pspp/src/lex/lexer.rs
index f335f67729..3e2b342596 100644
--- a/rust/pspp/src/lex/lexer.rs
+++ b/rust/pspp/src/lex/lexer.rs
@@ -6,7 +6,7 @@ use std::{
     io::Result as IoResult,
     iter::once,
     mem::take,
-    ops::{Bound, Range, RangeBounds, RangeInclusive},
+    ops::{Range, RangeBounds, RangeInclusive},
     path::Path,
     ptr,
     sync::Arc,
@@ -345,20 +345,14 @@ impl Debug for Tokens<'_> {
     }
 }
 
-impl Tokens<'_> {}
-
-pub struct NewLexer<'a> {
-    backing: &'a Tokens<'a>,
+pub struct TokenSlice<'a> {
     tokens: &'a [LexToken<'a>],
-    start: usize,
 }
 
-impl<'a> NewLexer<'a> {
+impl<'a> TokenSlice<'a> {
     pub fn new(backing: &'a Tokens) -> Self {
         Self {
-            backing,
             tokens: backing.tokens.as_slice(),
-            start: 0,
         }
     }
 
@@ -371,24 +365,16 @@ impl<'a> NewLexer<'a> {
         S: ToString,
         B: RangeBounds<usize>,
     {
-        self.sublexer(range)
+        self.subslice(range)
             .diagnostic(Severity::Error, text.to_string())
     }
 
-    pub fn sublexer<B>(&self, range: B) -> Self
+    pub fn subslice<B>(&self, range: B) -> Self
     where
         B: RangeBounds<usize>,
     {
         Self {
-            backing: self.backing,
-            start: self.start
-                + match range.start_bound() {
-                    Bound::Included(index) => *index,
-                    Bound::Excluded(index) => *index + 1,
-                    Bound::Unbounded => 0,
-                },
-            tokens: &self.backing.tokens
-                [(range.start_bound().cloned(), range.end_bound().cloned())],
+            tokens: &self.tokens[(range.start_bound().cloned(), range.end_bound().cloned())],
         }
     }
 
-- 
2.30.2