Remove useless trim function and unnecessary uses of eat_whitespace.

src/commands.rs

@@ -1,7 +1,6 @@
 use crate::cofd::dice::DicePool;
 use crate::dice::ElementExpression;
 use crate::help::HelpTopic;
-use crate::parser::trim;
 use crate::roll::Roll;
 
 pub mod parser;
@@ -84,18 +83,16 @@ impl Command for HelpCommand {
 /// Parse a command string into a dynamic command execution trait
 /// object. Returns an error if a command was recognized but not
 /// parsed correctly. Returns None if no command was recognized.
-pub fn parse_command<'a>(s: &'a str) -> Result<Option<Box<dyn Command + 'a>>, String> {
+pub fn parse_command(s: &str) -> Result<Option<Box<dyn Command>>, String> {
     match parser::parse_command(s) {
         Ok((input, command)) => match (input, &command) {
             //This clause prevents bot from spamming messages to itself
             //after executing a previous command.
             ("", Some(_)) | (_, None) => Ok(command),
 
-            //Any unconsumed input (except whitespace) is considered a parsing error.
-            (extra, _) => match trim(extra).as_str() {
-                "" => Ok(command),
-                _ => Err(format!("{}: malformed dice expression", s)),
-            },
+            //Any unconsumed input (whitespace should already be
+            // stripped) is considered a parsing error.
+            _ => Err(format!("{}: malformed expression", s)),
         },
         Err(err) => Err(err.to_string()),
     }

src/commands/parser.rs

@@ -2,18 +2,15 @@ use crate::cofd::parser::{create_chance_die, parse_dice_pool};
 use crate::commands::{Command, HelpCommand, PoolRollCommand, RollCommand};
 use crate::dice::parser::parse_element_expression;
 use crate::help::parse_help_topic;
-use crate::parser::{eat_whitespace, trim};
 use nom::{bytes::complete::tag, character::complete::alpha1, IResult};
 
 // Parse a roll expression.
 fn parse_roll(input: &str) -> IResult<&str, Box<dyn Command>> {
-    let (input, _) = eat_whitespace(input)?;
     let (input, expression) = parse_element_expression(input)?;
     Ok((input, Box::new(RollCommand(expression))))
 }
 
 fn parse_pool_roll(input: &str) -> IResult<&str, Box<dyn Command>> {
-    let (input, _) = eat_whitespace(input)?;
     let (input, pool) = parse_dice_pool(input)?;
     Ok((input, Box::new(PoolRollCommand(pool))))
 }
@@ -24,20 +21,20 @@ fn chance_die() -> IResult<&'static str, Box<dyn Command>> {
 }
 
 fn help(topic: &str) -> IResult<&str, Box<dyn Command>> {
-    let (topic, _) = eat_whitespace(topic)?;
-    let topic = parse_help_topic(&trim(topic));
+    let topic = parse_help_topic(topic);
     Ok(("", Box::new(HelpCommand(topic))))
 }
 
 /// Split an input string into its constituent command and "everything
 /// else" parts. Extracts the command separately from its input (i.e.
 /// rest of the line) and returns a tuple of (command_input, command).
+/// Whitespace at the start and end of the command input is removed.
 fn split_command(input: &str) -> IResult<&str, &str> {
-    let (input, _) = eat_whitespace(input)?;
+    //let (input, _) = eat_whitespace(input)?;
+    let input = input.trim_start();
     let (input, _) = tag("!")(input)?;
-    let (command_input, command) = alpha1(input)?;
-    let (command_input, _) = eat_whitespace(command_input)?;
-    //TODO strip witespace from end of command input
+    let (mut command_input, command) = alpha1(input)?;
+    command_input = command_input.trim();
     Ok((command_input, command))
 }
 
@@ -88,7 +85,6 @@ mod tests {
 
     #[test]
     fn whitespace_on_both_ends_test() {
-        //TODO currently it does not chop whitespace off the end.
         assert_eq!(
             ("1d4", "roll"),
             split_command("   !roll 1d4   ").expect("got parsing error")

src/parser.rs

@@ -9,24 +9,3 @@ pub fn eat_whitespace(input: &str) -> IResult<&str, &str> {
     let (input, whitespace) = take_while(is_whitespace)(input)?;
     Ok((input, whitespace))
 }
-
-/// Remove the whitespace on the ends of the string.
-pub fn trim(input: &str) -> String {
-    //2 allocations, how fun
-    String::from(input).trim().to_owned()
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn basic_trim_test() {
-        assert_eq!(String::from("blah"), trim("   blah   "));
-    }
-
-    #[test]
-    fn trim_only_removes_ends_test() {
-        assert_eq!(String::from("b l a h"), trim("   b l a h   "));
-    }
-}