A Rust crate to handle the eccentricities of BASIC input statements

Author: UncleScientist

00_Common/rust/Cargo.lock

@@ -0,0 +1,7 @@
+#
+# Although there is currently only the `basic_input` crate here, I am anticipating
+# more utility crates for rust ports, as well as proc macro crates.
+#
+[workspace]
+resolver = "2"
+members = [ "crates/basic_input" ]

00_Common/rust/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "basic_input"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

00_Common/rust/crates/basic_input/Cargo.toml

@@ -0,0 +1,354 @@
+mod input_state;
+mod io_layer;
+
+use input_state::InputState;
+use io_layer::IoLayer;
+
+/// Main entrypoint for this module. Display a prompt and read one or more values from the user.
+/// See [the crate docs](module@crate)
+pub fn get_input<BI: BasicInput, S: AsRef<str>>(prompt: S) -> BI {
+    let mut io = IoLayer::get_io();
+    get_input_from_io(prompt, &mut io)
+}
+
+// This is the trait that we return to the user, which allows us to have
+// a different function for each return type.
+// let one_input : f32 = get_input("...");
+// let (x, y) : (f32, f32) = get_input("...");
+// let (a, b, c) : (f32, f32, f32) = get_input("...");
+pub trait BasicInput {
+    fn from_string<S: AsRef<str>>(s: S, state: &mut InputState) -> Result<Self, BasicInputError>
+    where
+        Self: Sized;
+}
+
+// --------------------------------------------------------------------------------
+
+impl BasicInput for f32 {
+    fn from_string<S: AsRef<str>>(s: S, state: &mut InputState) -> Result<Self, BasicInputError> {
+        state.input_f32s(s, 1)?;
+        Ok(state.data[0].as_f32())
+    }
+}
+
+impl BasicInput for (f32, f32) {
+    fn from_string<S: AsRef<str>>(s: S, state: &mut InputState) -> Result<Self, BasicInputError> {
+        state.input_f32s(s, 2)?;
+
+        Ok((state.data[0].as_f32(), state.data[1].as_f32()))
+    }
+}
+
+impl BasicInput for (f32, f32, f32) {
+    fn from_string<S: AsRef<str>>(s: S, state: &mut InputState) -> Result<Self, BasicInputError> {
+        state.input_f32s(s, 3)?;
+
+        Ok((
+            state.data[0].as_f32(),
+            state.data[1].as_f32(),
+            state.data[2].as_f32(),
+        ))
+    }
+}
+
+impl BasicInput for (f32, f32, f32, f32) {
+    fn from_string<S: AsRef<str>>(s: S, state: &mut InputState) -> Result<Self, BasicInputError> {
+        state.input_f32s(s, 4)?;
+
+        Ok((
+            state.data[0].as_f32(),
+            state.data[1].as_f32(),
+            state.data[2].as_f32(),
+            state.data[3].as_f32(),
+        ))
+    }
+}
+
+impl BasicInput for (f32, f32, f32, f32, f32, f32, f32, f32, f32, f32) {
+    fn from_string<S: AsRef<str>>(s: S, state: &mut InputState) -> Result<Self, BasicInputError> {
+        state.input_f32s(s, 10)?;
+
+        Ok((
+            state.data[0].as_f32(),
+            state.data[1].as_f32(),
+            state.data[2].as_f32(),
+            state.data[3].as_f32(),
+            state.data[4].as_f32(),
+            state.data[5].as_f32(),
+            state.data[6].as_f32(),
+            state.data[7].as_f32(),
+            state.data[8].as_f32(),
+            state.data[9].as_f32(),
+        ))
+    }
+}
+
+impl BasicInput for String {
+    fn from_string<S: AsRef<str>>(s: S, state: &mut InputState) -> Result<Self, BasicInputError> {
+        state.input_strings(s, 1)?;
+        Ok(state.data[0].as_string())
+    }
+}
+
+impl BasicInput for (String, String) {
+    fn from_string<S: AsRef<str>>(s: S, state: &mut InputState) -> Result<Self, BasicInputError> {
+        state.input_strings(s, 2)?;
+        Ok((state.data[0].as_string(), state.data[1].as_string()))
+    }
+}
+
+// --------------------------------------------------------------------------------
+
+fn get_input_from_io<BI: BasicInput, S: AsRef<str>>(prompt: S, io: &mut IoLayer) -> BI {
+    let mut state = InputState {
+        io,
+        data: Vec::new(),
+    };
+
+    state.io.raw_output_string(format!("{}? ", prompt.as_ref()));
+
+    loop {
+        let buffer = state.io.raw_input_string();
+        match BI::from_string(buffer, &mut state) {
+            Ok(result) => return result,
+            Err(e) => match e {
+                BasicInputError::ParseFailed => {
+                    state.io.raw_output_string("?REENTER\n");
+                    state.io.raw_output_string(format!("{}? ", prompt.as_ref()));
+                    state.data.clear();
+                }
+                BasicInputError::MissingInput => {
+                    state.io.raw_output_string("??? ");
+                }
+            },
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum BasicInputError {
+    ParseFailed,
+    MissingInput,
+}
+
+#[cfg(test)]
+mod test {
+    use crate::input::get_input_from_io;
+    use crate::input::io_layer::{IoLayer, TextInput, TextOutput};
+    use std::collections::VecDeque;
+
+    fn getio() -> IoLayer {
+        IoLayer {
+            output: Box::new(WriteTestLayer::new()),
+            input: Box::new(ReadTestLayer::new()),
+        }
+    }
+
+    #[test]
+    fn test_trait_single_input() {
+        let mut testio = getio();
+        testio.input.set_input_text("2");
+        let result: f32 = get_input_from_io("prompt", &mut testio);
+        assert_eq!(2.0, result);
+    }
+
+    #[test]
+    fn test_trait_dual_input() {
+        let mut testio = getio();
+        testio.input.set_input_text("2,3");
+        let result: (f32, f32) = get_input_from_io("prompt", &mut testio);
+        assert_eq!(
+            "prompt? ".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!(2.0, result.0);
+        assert_eq!(3.0, result.1);
+    }
+
+    #[test]
+    fn test_invalid_input() {
+        let mut testio = getio();
+        testio.input.set_input_text("abc");
+        testio.input.set_input_text("2");
+        let result: f32 = get_input_from_io("prompt", &mut testio);
+        assert_eq!(
+            "prompt? ".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!(
+            "?REENTER\n".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!(2.0, result);
+    }
+
+    #[test]
+    fn test_multiple_invalid_input() {
+        let mut testio = getio();
+        testio.input.set_input_text("abc");
+        testio.input.set_input_text("2,a");
+        testio.input.set_input_text("2,3");
+        let result: (f32, f32) = get_input_from_io("prompt", &mut testio);
+        assert_eq!(
+            "prompt? ".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!(
+            "?REENTER\n".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!(
+            "prompt? ".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!(
+            "?REENTER\n".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!(
+            "prompt? ".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!(2.0, result.0);
+        assert_eq!(3.0, result.1);
+    }
+
+    #[test]
+    fn two_inputs_over_multiple_lines() {
+        let mut testio = getio();
+        testio.input.set_input_text("2");
+        testio.input.set_input_text("3");
+        let result: (f32, f32) = get_input_from_io("prompt", &mut testio);
+        assert_eq!(
+            "prompt? ".to_string(),
+            testio.output.get_last_line().unwrap()
+        );
+        assert_eq!("??? ".to_string(), testio.output.get_last_line().unwrap());
+        assert_eq!(2.0, result.0);
+        assert_eq!(3.0, result.1);
+    }
+
+    #[test]
+    fn test_triple_f32() {
+        let mut testio = getio();
+        testio.input.set_input_text("1, 2, 3");
+        let result: (f32, f32, f32) = get_input_from_io("enter 3 numbers", &mut testio);
+        assert_eq!(1.0, result.0);
+        assert_eq!(2.0, result.1);
+        assert_eq!(3.0, result.2);
+    }
+
+    #[test]
+    fn test_input_string() {
+        let mut testio = getio();
+        testio.input.set_input_text("hello");
+        let result: String = get_input_from_io("String prompt", &mut testio);
+        assert_eq!("hello".to_string(), result);
+    }
+
+    #[test]
+    fn test_two_input_strings() {
+        let mut testio = getio();
+        testio.input.set_input_text("hello, world");
+        let result: (String, String) = get_input_from_io("Double string prompt", &mut testio);
+        assert_eq!("hello".to_string(), result.0);
+        assert_eq!("world".to_string(), result.1);
+    }
+
+    #[test]
+    fn test_four_nums() {
+        let mut testio = getio();
+        testio.input.set_input_text("1, 2, 3, 4");
+        let result: (f32, f32, f32, f32) = get_input_from_io("whatever", &mut testio);
+        assert_eq!(4.0, result.3);
+    }
+
+    #[test]
+    fn test_extra_ignored() {
+        let mut testio = getio();
+        testio.input.set_input_text("1, 2, 3, 4");
+        let result: (f32, f32) = get_input_from_io("whatever", &mut testio);
+        assert_eq!(Some("whatever? "), testio.output.get_last_line().as_deref());
+        assert_eq!(
+            Some("?EXTRA IGNORED\n"),
+            testio.output.get_last_line().as_deref()
+        );
+        assert_eq!(2.0, result.1);
+    }
+
+    #[test]
+    fn test_extra_ignored_bad_parse() {
+        let mut testio = getio();
+        testio.input.set_input_text("1, 2, hello");
+        let result: (f32, f32) = get_input_from_io("whatever", &mut testio);
+        assert_eq!(Some("whatever? "), testio.output.get_last_line().as_deref());
+        assert_eq!(
+            Some("?EXTRA IGNORED\n"),
+            testio.output.get_last_line().as_deref()
+        );
+        assert_eq!(2.0, result.1);
+    }
+
+    #[test]
+    fn test_ten_nums() {
+        let mut testio = getio();
+        testio.input.set_input_text("1, 2, 3, 4, 5, 6, 7, 8, 9, 10");
+        let result: (f32, f32, f32, f32, f32, f32, f32, f32, f32, f32) =
+            get_input_from_io("whatever", &mut testio);
+        assert_eq!(Some("whatever? "), testio.output.get_last_line().as_deref());
+        assert_eq!(None, testio.output.get_last_line());
+        assert_eq!(10.0, result.9);
+    }
+
+    //
+    // Helpers for test i/o
+    //
+    pub struct ReadTestLayer {
+        next_line: VecDeque<String>,
+    }
+
+    impl ReadTestLayer {
+        pub fn new() -> Self {
+            Self {
+                next_line: VecDeque::new(),
+            }
+        }
+    }
+
+    impl TextInput for ReadTestLayer {
+        fn read(&mut self) -> String {
+            if let Some(line) = self.next_line.pop_front() {
+                println!(">> returning {line}");
+                line
+            } else {
+                panic!("Test tried to read too much input");
+            }
+        }
+
+        fn set_input_text(&mut self, text: &str) {
+            self.next_line.push_back(text.to_string());
+        }
+    }
+
+    pub struct WriteTestLayer {
+        last_items_written: VecDeque<String>,
+    }
+
+    impl WriteTestLayer {
+        pub fn new() -> Self {
+            Self {
+                last_items_written: VecDeque::new(),
+            }
+        }
+    }
+
+    impl TextOutput for WriteTestLayer {
+        fn write(&mut self, to_write: &str) {
+            self.last_items_written.push_back(to_write.into());
+        }
+
+        fn get_last_line(&mut self) -> Option<String> {
+            self.last_items_written.pop_front()
+        }
+    }
+}