Split parse state validation and make parse context arg optional.

jaarg-nostd/examples/basic_nostd.rs

@@ -44,9 +44,9 @@ extern "C" fn safe_main(args: &[&str]) -> ExitCode {
           print!("{}", StandardFullHelpWriter::<'_, Arg>::new(ctx));
           return Ok(ParseControl::Quit);
         }
-        Arg::Number => { number = str::parse(ctx.arg)?; }
+        Arg::Number => { number = str::parse(ctx.arg.unwrap())?; }
-        Arg::File   => { file = ctx.arg.into(); }
+        Arg::File   => { file = ctx.arg.unwrap().into(); }
-        Arg::Out    => { out = Some(ctx.arg.into()); }
+        Arg::Out    => { out = Some(ctx.arg.unwrap().into()); }
       }
       Ok(ParseControl::Continue)
     }, |program_name, error| {

jaarg/examples/basic.rs

@@ -32,15 +32,15 @@ fn main() {
         OPTIONS.print_full_help(ctx.program_name);
         return Ok(ParseControl::Quit);
       }
-      Arg::Number => { number = str::parse(ctx.arg)?; }
+      Arg::Number => { number = str::parse(ctx.arg.unwrap().as_ref())?; }
-      Arg::File   => { file = ctx.arg.into(); }
+      Arg::File   => { file = ctx.arg.unwrap().into(); }
-      Arg::Out    => { out = Some(ctx.arg.into()); }
+      Arg::Out    => { out = Some(ctx.arg.unwrap().into()); }
     }
     Ok(ParseControl::Continue)
   }) {
     ParseResult::ContinueSuccess => (),
-    ParseResult::ExitSuccess     => std::process::exit(0),
+    ParseResult::ExitSuccess => std::process::exit(0),
-    ParseResult::ExitFailure     => std::process::exit(1),
+    ParseResult::ExitFailure => std::process::exit(1),
   }
 
   // Print the result variables

jaarg/examples/bin2h.rs

@@ -212,10 +212,10 @@ pub fn main() -> ExitCode {
                        as arrays and C strings respectively.");
   match OPTIONS.parse_easy(|ctx| {
     match ctx.id {
-      Arg::Out => { arguments.out = ctx.arg.into(); }
+      Arg::Out => { arguments.out = ctx.arg.unwrap().into(); }
-      Arg::Bin => { jobs.push(Job { job_type: JobType::Binary, path: ctx.arg.into() }); }
+      Arg::Bin => { jobs.push(Job { job_type: JobType::Binary, path: ctx.arg.unwrap().into() }); }
-      Arg::Txt => { jobs.push(Job { job_type: JobType::Text, path: ctx.arg.into() }); }
+      Arg::Txt => { jobs.push(Job { job_type: JobType::Text, path: ctx.arg.unwrap().into() }); }
-      Arg::Whitespace => { arguments.whitespace = ctx.arg.into(); }
+      Arg::Whitespace => { arguments.whitespace = ctx.arg.unwrap().into(); }
       Arg::Help => {
         OPTIONS.print_full_help(ctx.program_name);
         return Ok(ParseControl::Quit);

jaarg/src/alloc.rs

@@ -5,9 +5,9 @@
 
 extern crate alloc;
 
-use alloc::collections::BTreeMap;
-use alloc::string::String;
 use crate::{Opts, ParseControl, ParseError, ParseResult};
+use alloc::collections::BTreeMap;
+use alloc::string::{String, ToString};
 
 impl Opts<&'static str> {
   /// Parse an iterator of strings as arguments and return the results in a [`BTreeMap`].
@@ -22,7 +22,7 @@ impl Opts<&'static str> {
         help(program_name);
         Ok(ParseControl::Quit)
       } else {
-        out.insert(ctx.id, ctx.arg.into());
+        out.insert(ctx.id, ctx.arg.unwrap().to_string());
         Ok(ParseControl::Continue)
       }
     }, error) {

jaarg/src/argparse.rs

@@ -39,8 +39,8 @@ pub struct ParseHandlerContext<'a, ID: 'static> {
   /// The name of the argument parameter that was matched,
   /// for option parameters this is the token supplied by the user.
   pub name: &'a str,
-  /// The argument provided to positional arguments and value options, else "".
+  /// The argument provided to positional arguments and value options (will always be Some), or None for flags.
-  pub arg: &'a str,
+  pub arg: Option<&'a str>,
 }
 
 /// Result type used by the handler passed to the parser.
@@ -151,6 +151,11 @@ impl<ID: 'static> Opts<ID> {
       }
     }
 
+    self.validate_state(program_name, state, error)
+  }
+
+  fn validate_state(&self, program_name: &str, mut state: ParserState<ID>, error: impl FnOnce(&str, ParseError)
+  ) -> ParseResult {
     // Ensure that value options are provided a value
     if let Some((name, _)) = state.expects_arg.take() {
       error(program_name, ParseError::ExpectArgument(name));
@@ -188,7 +193,7 @@ impl<ID: 'static> Opts<ID> {
         // HACK: Ensure the string fields are set properly, because coerced
         //       ParseIntError/ParseFloatError will have the string fields blanked.
         Err(ParseError::ArgumentError("", "", kind))
-          => Err(ParseError::ArgumentError(name, value, kind)),
+          => Err(ParseError::ArgumentError(name, value.unwrap(), kind)),
         Err(err) => Err(err),
         Ok(ctl) => Ok(ctl),
       }
@@ -198,7 +203,7 @@ impl<ID: 'static> Opts<ID> {
     //  was matched and didn't have an equals sign separating a value,
     //  then call the handler here.
     if let Some((name, option)) = state.expects_arg.take() {
-      call_handler(option, name, token)
+      call_handler(option, name, Some(token))
     } else {
       // Check if the next argument token starts with an option flag
       if self.flag_chars.chars().any(|c| token.starts_with(c)) {
@@ -230,9 +235,9 @@ impl<ID: 'static> Opts<ID> {
 
         match (&option.r#type, value_str) {
           // Call handler for flag-only options
-          (OptType::Flag, None) => call_handler(option, name, ""),
+          (OptType::Flag, None) => call_handler(option, name, None),
           // Value was provided this token, so call the handler right now
-          (OptType::Value, Some(value)) => call_handler(option, name, value),
+          (OptType::Value, Some(value)) => call_handler(option, name, Some(value)),
           // No value available in this token, delay handling to next token
           (OptType::Value, None) => {
             state.expects_arg = Some((name, option));
@@ -247,7 +252,7 @@ impl<ID: 'static> Opts<ID> {
         // Find the next positional argument
         for (i, option) in self.options[state.positional_index..].iter().enumerate() {
           if matches!(option.r#type, OptType::Positional) {
-            call_handler(option, option.first_name(), token)?;
+            call_handler(option, option.first_name(), Some(token))?;
             state.positional_index += i + 1;
             return Ok(ParseControl::Continue);
           }
@@ -260,12 +265,13 @@ impl<ID: 'static> Opts<ID> {
 
 #[cfg(test)]
 mod tests {
-  extern crate alloc;
-  use alloc::string::String;
   use super::*;
 
   #[test]
-  fn test() {
+  fn test_parse() {
+    extern crate alloc;
+    use alloc::string::String;
+
     enum ArgID { One, Two, Three, Four, Five }
     const OPTIONS: Opts<ArgID> = Opts::new(&[
       Opt::positional(ArgID::One, "one"),
@@ -284,11 +290,11 @@ mod tests {
     let mut five: Option<String> = None;
     assert!(matches!(OPTIONS.parse("", ARGUMENTS.iter(), |ctx| {
       match ctx.id {
-        ArgID::One =>   { one = Some(ctx.arg.into()); }
+        ArgID::One =>   { one = Some(ctx.arg.unwrap().into()); }
         ArgID::Two =>   { two = true; }
-        ArgID::Three => { three = Some(ctx.arg.into()); }
+        ArgID::Three => { three = Some(ctx.arg.unwrap().into()); }
-        ArgID::Four =>  { four = Some(ctx.arg.into()); }
+        ArgID::Four =>  { four = Some(ctx.arg.unwrap().into()); }
-        ArgID::Five =>  { five = Some(ctx.arg.into()); }
+        ArgID::Five =>  { five = Some(ctx.arg.unwrap().into()); }
       }
       Ok(ParseControl::Continue)
     }, |_, error| {