From f3c491d1f98f7333f312dda92b80ac25b8f9d10e Mon Sep 17 00:00:00 2001
From: darcy <acednes@gmail.com>
Date: Thu, 19 Dec 2024 11:31:55 +1100
Subject: [PATCH] feat!: read commands from argument first, then read from
 stdin/terminal

---
 src/debugger/eval.rs   |  2 -
 src/debugger/mod.rs    |  6 +--
 src/debugger/source.rs | 97 ++++++++++++++++++++++++++++--------------
 3 files changed, 67 insertions(+), 38 deletions(-)

diff --git a/src/debugger/eval.rs b/src/debugger/eval.rs
index 0e0bb38..82131d6 100644
--- a/src/debugger/eval.rs
+++ b/src/debugger/eval.rs
@@ -5,8 +5,6 @@ use crate::runtime::RunState;
 use crate::symbol::Span;
 use crate::{dprintln, AsmParser};
 
-// TODO(feat): Warn on `eval br* ...` and suggest `jump ...`
-
 pub fn eval(state: &mut RunState, line: String) {
     // Required to make temporarily 'static
     // Automatically dropped at end of scope
diff --git a/src/debugger/mod.rs b/src/debugger/mod.rs
index 3836444..e65f242 100644
--- a/src/debugger/mod.rs
+++ b/src/debugger/mod.rs
@@ -4,7 +4,7 @@ mod parse;
 mod source;
 
 use self::command::{Command, Label, Location, MemoryLocation};
-use self::source::{SourceMode, SourceReader};
+use self::source::{Source, SourceReader};
 use crate::air::AsmLine;
 use crate::dprintln;
 use crate::output::{Condition, Output};
@@ -19,7 +19,7 @@ pub struct DebuggerOptions {
 
 pub struct Debugger {
     status: Status,
-    source: SourceMode,
+    source: Source,
 
     // TODO(refactor): Make private, use method to increment
     pub(super) instruction_count: u32,
@@ -163,7 +163,7 @@ impl Debugger {
     ) -> Self {
         Self {
             status: Status::default(),
-            source: SourceMode::from(opts.command),
+            source: Source::from(opts.command),
             instruction_count: 0,
             was_pc_changed: true,
             initial_state,
diff --git a/src/debugger/source.rs b/src/debugger/source.rs
index de7a620..22e11fb 100644
--- a/src/debugger/source.rs
+++ b/src/debugger/source.rs
@@ -5,23 +5,19 @@ use console::Key;
 
 use crate::{dprint, dprintln, output::Output};
 
-// TODO(feat): If argument ends in '...' (or something) then switch to `SourceMode::Terminal` once
-// arguments are exhausted
-
+/// Read from argument first, if `Some`. Then read from stream.
 #[allow(private_interfaces)] // Perhaps a bad practice
 #[derive(Debug)]
-pub enum SourceMode {
-    Argument(Argument),
-    Stdin(Stdin),
-    Terminal(Terminal),
+pub struct Source {
+    argument: Option<Argument>,
+    stream: Stream,
 }
 
-/// Stdin which is not attached to a terminal, i.e. piped.
+/// Stdin or interactive terminal
 #[derive(Debug)]
-struct Stdin {
-    stdin: io::Stdin,
-    /// Command must be stored somewhere to be referenced
-    buffer: String,
+enum Stream {
+    Stdin(Stdin),
+    Terminal(Terminal),
 }
 
 /// Command-line argument
@@ -32,6 +28,14 @@ struct Argument {
     cursor: usize,
 }
 
+/// Stdin which is not attached to a terminal, i.e. piped.
+#[derive(Debug)]
+struct Stdin {
+    stdin: io::Stdin,
+    /// Command must be stored somewhere to be referenced
+    buffer: String,
+}
+
 /// Interactive unbuffered terminal
 // TODO(feat): Support CTRL+Arrow keybinds
 #[derive(Debug)]
@@ -51,44 +55,71 @@ struct Terminal {
     history_file: File,
 }
 
+fn echo_command_prompt(command: Option<&str>) {
+    // Echo prompt and command for non-terminal source
+    // Equivalent code found in terminal source
+    if !Output::is_minimal() || command.is_some() {
+        dprint!(Always, Normal, "\x1b[1mCommand: ");
+        dprintln!(
+            Always,
+            Normal,
+            "{}",
+            command.unwrap_or("\x1b[3m(end of input)").trim()
+        );
+    }
+}
+
 pub trait SourceReader {
     /// `None` indicates EOF
     /// Returned string slice MAY include leading or trailing whitespace
     fn read(&mut self) -> Option<&str>;
 }
 
-impl SourceMode {
+impl Source {
     pub fn from(argument: Option<String>) -> Self {
-        if let Some(argument) = argument {
-            return SourceMode::Argument(Argument::from(argument));
+        Self {
+            argument: argument.map(|argument| Argument::from(argument)),
+            stream: Stream::new(),
         }
+    }
+}
+
+impl SourceReader for Source {
+    fn read(&mut self) -> Option<&str> {
+        // Always try to read from argument first
+        // If argument is `None`, or if read from argument returns `None`, then read from stream
+        // Note that `self.argument` cannot then be set to `None`, due to lifetime of returned value
+        if let Some(argument) = &mut self.argument {
+            if let Some(command) = argument.read() {
+                echo_command_prompt(Some(command));
+                return Some(command);
+            }
+        }
+        self.stream.read()
+    }
+}
+
+impl Stream {
+    pub fn new() -> Self {
         let stdin = io::stdin();
         if stdin.is_terminal() {
-            return SourceMode::Terminal(Terminal::new());
+            return Self::Terminal(Terminal::new());
         }
-        SourceMode::Stdin(Stdin::from(stdin))
+        Self::Stdin(Stdin::from(stdin))
     }
 }
 
-impl SourceReader for SourceMode {
+impl SourceReader for Stream {
     fn read(&mut self) -> Option<&str> {
-        let command = match self {
-            Self::Argument(argument) => argument.read(),
-            Self::Stdin(stdin) => stdin.read(),
+        match self {
+            Self::Stdin(stdin) => {
+                let command = stdin.read();
+                echo_command_prompt(command);
+                command
+            }
+            // Don't echo command for terminal source, that would be redundant
             Self::Terminal(terminal) => return terminal.read(),
-        };
-        // Echo prompt and command for non-terminal source
-        // Equivalent code found in terminal source
-        if !Output::is_minimal() || command.is_some() {
-            dprint!(Always, Normal, "\x1b[1mCommand: ");
-            dprintln!(
-                Always,
-                Normal,
-                "{}",
-                command.unwrap_or("\x1b[3m(end of input)").trim()
-            );
         }
-        command
     }
 }