Provide Position to debug.

src/engine.rs

@@ -4,7 +4,8 @@ use crate::ast::{Expr, FnCallExpr, Ident, IdentX, ReturnType, Stmt};
 use crate::dynamic::{map_std_type_name, AccessMode, Union, Variant};
 use crate::fn_call::run_builtin_op_assignment;
 use crate::fn_native::{
-    CallableFunction, IteratorFn, OnPrintCallback, OnProgressCallback, OnVarCallback,
+    CallableFunction, IteratorFn, OnDebugCallback, OnPrintCallback, OnProgressCallback,
+    OnVarCallback,
 };
 use crate::module::NamespaceRef;
 use crate::optimize::OptimizationLevel;
@@ -626,7 +627,7 @@ pub struct Engine {
     /// Callback closure for implementing the `print` command.
     pub(crate) print: OnPrintCallback,
     /// Callback closure for implementing the `debug` command.
-    pub(crate) debug: OnPrintCallback,
+    pub(crate) debug: OnDebugCallback,
     /// Callback closure for progress reporting.
     pub(crate) progress: Option<OnProgressCallback>,
 
@@ -677,7 +678,7 @@ pub fn is_anonymous_fn(fn_name: &str) -> bool {
     fn_name.starts_with(FN_ANONYMOUS)
 }
 
-/// Print/debug to stdout
+/// Print to stdout
 #[inline(always)]
 fn default_print(_s: &str) {
     #[cfg(not(feature = "no_std"))]
@@ -685,6 +686,14 @@ fn default_print(_s: &str) {
     println!("{}", _s);
 }
 
+/// Debug to stdout
+#[inline(always)]
+fn default_debug(_s: &str, _pos: Position) {
+    #[cfg(not(feature = "no_std"))]
+    #[cfg(not(target_arch = "wasm32"))]
+    println!("{:?} | {}", _pos, _s);
+}
+
 /// Search for a module within an imports stack.
 /// [`Position`] in [`EvalAltResult`] is [`None`][Position::None] and must be set afterwards.
 pub fn search_imports(
@@ -741,7 +750,7 @@ impl Engine {
 
             // default print/debug implementations
             print: Box::new(default_print),
-            debug: Box::new(default_print),
+            debug: Box::new(default_debug),
 
             // progress callback
             progress: None,
@@ -797,7 +806,7 @@ impl Engine {
             resolve_var: None,
 
             print: Box::new(|_| {}),
-            debug: Box::new(|_| {}),
+            debug: Box::new(|_, _| {}),
             progress: None,
 
             optimization_level: if cfg!(feature = "no_optimize") {