Add debug variable locations tracking

Cargo.toml

@@ -41,7 +41,7 @@ name = "miden-debug"
 path = "src/main.rs"
 test = false
 bench = false
-required-features = ["tui"]
+required-features = ["std"]
 
 [[example]]
 name = "compile-masm"
@@ -50,6 +50,7 @@ required-features = ["std"]
 [features]
 default = ["tui", "dap"]
 tui = ["std", "dep:crossterm", "dep:env_logger", "dep:ratatui", "dep:tui-input", "dep:signal-hook", "dep:syntect", "miden-debug-engine/tui"]
+repl = ["std", "dep:env_logger", "dep:rustyline", "miden-debug-engine/tui"]
 dap = ["dep:dap", "dep:socket2", "miden-debug-engine/dap"]
 std = ["dep:glob", "clap/std", "clap/env", "compact_str/std", "miden-assembly-syntax/std", "miden-debug-engine/std"]
 proptest = ["dep:proptest", "miden-debug-engine/proptest"]
@@ -97,6 +98,7 @@ syntect = { version = "5.2.0", optional = true, default-features = false, featur
 thiserror = { package = "miden-thiserror", version = "1.0" }
 toml = { version = "0.8", features = ["preserve_order"] }
 tui-input = { version = "0.11", optional = true }
+rustyline = { version = "15.0", optional = true }
 
 socket2 = { version = "0.5", optional = true }
 tokio = { version = "1.39.2", features = ["rt", "time", "macros", "rt-multi-thread"] }

crates/engine/src/debug/breakpoint.rs

@@ -54,6 +54,8 @@ pub enum BreakpointType {
     StepTo(usize),
     /// Break at the first cycle of the next instruction
     Next,
+    /// Break at the next source line, or the next instruction if no source location is available.
+    NextLine,
     /// Break when we exit the current call frame
     Finish,
     /// Break when any cycle corresponds to a source location whose file matches PATTERN
@@ -100,14 +102,21 @@ impl BreakpointType {
 
     /// Returns true if this breakpoint is internal to the debugger (i.e. not creatable via :b)
     pub fn is_internal(&self) -> bool {
-        matches!(self, BreakpointType::Next | BreakpointType::Step | BreakpointType::Finish)
+        matches!(
+            self,
+            BreakpointType::Next
+                | BreakpointType::NextLine
+                | BreakpointType::Step
+                | BreakpointType::Finish
+        )
     }
 
     /// Returns true if this breakpoint is removed upon being hit
     pub fn is_one_shot(&self) -> bool {
         matches!(
             self,
             BreakpointType::Next
+                | BreakpointType::NextLine
                 | BreakpointType::Finish
                 | BreakpointType::Step
                 | BreakpointType::StepN(_)

crates/engine/src/debug/mod.rs

@@ -2,6 +2,7 @@ mod breakpoint;
 mod memory;
 mod native_ptr;
 mod stacktrace;
+mod variables;
 
 pub use self::{
     breakpoint::{Breakpoint, BreakpointType},
@@ -11,4 +12,5 @@ pub use self::{
         CallFrame, CallStack, ControlFlowOp, CurrentFrame, OpDetail, ResolvedLocation, StackTrace,
         StepInfo,
     },
+    variables::{DebugVarSnapshot, DebugVarTracker, resolve_variable_value},
 };