From 77b8a92e034a5cc574a549cd5e7f5453f64461e535e503d8b75a71d534e962f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20Bj=C3=B6rnstam?= <linus.internet@fastmail.se>
Date: Fri, 16 Oct 2026 09:35:25 +0200
Subject: [PATCH] Debugging with dape and netcoredbg, and the compiler's new
 options
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emacs/bjolang-dape.el adds a dape configuration that builds the current
file with -d and runs it under netcoredbg, launching dotnet with the
program, which is a managed assembly rather than a native host. The
README says what a debugger shows today.

The check builds its options from Build.dependencyOptions, now that the
compiler's options have grown the dump flags.

🤖 Generated with [ECA](https://eca.dev)

Co-Authored-By: eca-agent <git@eca.dev>
---
 Check.fs              |  7 +----
 README.md             | 13 +++++++++
 emacs/bjolang-dape.el | 63 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+), 6 deletions(-)
 create mode 100644 emacs/bjolang-dape.el

diff --git a/Check.fs b/Check.fs
index c5ec18a..33f1226 100644
--- a/Check.fs
+++ b/Check.fs
@@ -98,12 +98,7 @@ let private found (file: string) (d: Diagnostics.Diagnostic) : Found =
           IsError = isError
           Message = d.Message + where }
 
-let private options: Build.Options =
-    { IsLibrary = false
-      Debug = false
-      Runtime = []
-      EmitCs = None
-      Check = true }
+let private options: Build.Options = { Build.dependencyOptions with IsLibrary = false; Check = true }
 
 /// Checks `file` as `bjolang --check` does, reading every file in `buffers`,
 /// by full path, from there rather than from disk: the editor's unsaved text,
diff --git a/README.md b/README.md
index 878e7fc..130bd84 100644
--- a/README.md
+++ b/README.md
@@ -94,6 +94,19 @@ stdout, and logs to stderr.
 (add-hook 'bjo-mode-hook #'lsp)
 ```
 
+`emacs/bjolang-dape.el` debugs a program with `dape` and
+[netcoredbg](https://github.com/Samsung/netcoredbg/releases):
+
+```elisp
+(load "/home/linis/Programmering/BjolangLsp/emacs/bjolang-dape.el")
+```
+
+`M-x dape RET bjolang RET` in a file with a `main` builds it with `-d` and
+runs it under the debugger. Breakpoints in the `.bjo` file bind, stepping
+goes by its lines, and the call stack names them. The locals are the
+generated C#'s, compiler temporaries included, and values show as their C#
+types, which expand into their fields.
+
 With eglot instead:
 
 ```elisp
diff --git a/emacs/bjolang-dape.el b/emacs/bjolang-dape.el
new file mode 100644
index 0000000..40c8c1b
--- /dev/null
+++ b/emacs/bjolang-dape.el
@@ -0,0 +1,63 @@
+;;; bjolang-dape.el --- Debugging Bjolang programs with dape and netcoredbg -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;; `M-x dape RET bjolang RET' in a Bjolang buffer builds the file with `-d'
+;; and runs it under netcoredbg.  A breakpoint set in the `.bjo' file binds,
+;; stepping goes by its lines, and the call stack names them: the compiler
+;; maps the generated C# back to the source with `#line', and a debug build
+;; writes that mapping into the program's PDB.
+;;
+;; The file has to be a program, one with a `main'.  The program is a
+;; managed assembly that `dotnet' runs, so that is what netcoredbg is told
+;; to start, with the program as its argument.
+;;
+;; netcoredbg: https://github.com/Samsung/netcoredbg/releases, unpacked so
+;; that `bjo-netcoredbg' names the executable.
+
+;;; Code:
+
+(defgroup bjolang-dape nil
+  "Debugging Bjolang programs."
+  :group 'tools)
+
+(defcustom bjo-compiler "~/Programmering/Bjolang/bin/compiler/Bjolang.dll"
+  "The Bjolang compiler, as `build_compiler.sh --path' prints it."
+  :type 'file)
+
+(defcustom bjo-netcoredbg "~/.local/share/netcoredbg/netcoredbg"
+  "The netcoredbg executable."
+  :type 'file)
+
+(defun bjo--dape-source ()
+  "The Bjolang file a debug session is started from."
+  (or (buffer-file-name) (user-error "Not visiting a Bjolang file")))
+
+(defun bjo--dape-program ()
+  "The program a debug build of the current file produces."
+  (concat (file-name-sans-extension (bjo--dape-source)) ".exe"))
+
+(defun bjo--dape-compile-command ()
+  "The debug build of the current file."
+  (format "dotnet %s -d %s"
+          (shell-quote-argument (expand-file-name bjo-compiler))
+          (shell-quote-argument (bjo--dape-source))))
+
+(with-eval-after-load 'dape
+  (add-to-list 'dape-configs
+               `(bjolang
+                 modes (bjo-mode)
+                 command ,(expand-file-name bjo-netcoredbg)
+                 command-args ["--interpreter=vscode"]
+                 compile bjo--dape-compile-command
+                 :request "launch"
+                 :type "coreclr"
+                 :cwd (lambda () (file-name-directory (bjo--dape-source)))
+                 :program "dotnet"
+                 :args [bjo--dape-program]
+                 :justMyCode t
+                 :stopAtEntry nil)))
+
+(provide 'bjolang-dape)
+
+;;; bjolang-dape.el ends here