From 6152b0bd5786614ee038a1b24bf1a5c3c7e029d1 Mon Sep 17 00:00:00 2001
From: s-hadinger <49731213+s-hadinger@users.noreply.github.com>
Date: Wed, 24 Jan 2024 08:39:45 +0100
Subject: [PATCH] Add `debug.caller()` (#390)

* Add `debug.caller()`

* fix non-precompiled
---
 src/be_debuglib.c | 23 +++++++++++++++++++++++
 tests/debug.be    | 27 ++++++++++++++++++++++++++-
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/src/be_debuglib.c b/src/be_debuglib.c
index fac4bfb5..2e4ee9bf 100644
--- a/src/be_debuglib.c
+++ b/src/be_debuglib.c
@@ -13,6 +13,7 @@
 #include "be_debug.h"
 #include "be_map.h"
 #include "be_vm.h"
+#include "be_exec.h"
 #include <string.h>
 
 #if BE_USE_DEBUG_MODULE
@@ -103,6 +104,26 @@ static int m_traceback(bvm *vm)
     be_return_nil(vm);
 }
 
+static int m_caller(bvm *vm)
+{
+    int depth = 1;
+    if (be_top(vm) >= 1 && be_isint(vm, 1)) {
+        depth = be_toint(vm, 1);
+        if (depth < 0) {
+            depth = -depth;         /* take absolute value */
+        }
+    }
+    bcallframe *cf = (bcallframe*)be_stack_top(&vm->callstack) - depth;
+    bcallframe *base = be_stack_base(&vm->callstack);
+    if (cf >= base) {
+        bvalue *reg = be_incrtop(vm);
+        var_setval(reg, cf->func);
+        be_return(vm);
+    } else {
+        be_return_nil(vm);
+    }
+}
+
 #if BE_USE_DEBUG_HOOK
 static int m_sethook(bvm *vm)
 {
@@ -236,6 +257,7 @@ be_native_module_attr_table(debug) {
     be_native_module_function("varname", m_varname),
     be_native_module_function("upvname", m_upvname)
 #endif
+    be_native_module_function("caller", m_caller),
     be_native_module_function("gcdebug", m_gcdebug)
 };
 
@@ -252,6 +274,7 @@ module debug (scope: global, depend: BE_USE_DEBUG_MODULE) {
     top, func(m_top)
     varname, func(m_varname), BE_DEBUG_VAR_INFO
     upvname, func(m_upvname), BE_DEBUG_VAR_INFO
+    caller, func(m_caller)
     // individual counters
     allocs, func(m_allocs)
     frees, func(m_frees)
diff --git a/tests/debug.be b/tests/debug.be
index 9e732f6c..88b559d8 100644
--- a/tests/debug.be
+++ b/tests/debug.be
@@ -1,4 +1,29 @@
 import debug
 
 class A end
-debug.attrdump(A)   #- should not crash -#
\ No newline at end of file
+debug.attrdump(A)   #- should not crash -#
+
+# debug.caller()
+def caller_name_chain()
+    import debug
+    import introspect
+    var i = 1
+    var ret = []
+    var caller = debug.caller(i)
+    while caller
+        ret.push(introspect.name(caller))
+        i += 1
+        caller = debug.caller(i)
+    end
+    return ret
+end
+var chain = caller_name_chain()
+assert(chain[0] == 'caller_name_chain')
+
+def guess_my_name__()
+    return caller_name_chain()
+end
+chain = guess_my_name__()
+print(chain)
+assert(chain[0] == 'caller_name_chain')
+assert(chain[1] == 'guess_my_name__')