From 0438c63fa8d379500d3a724c4b349dc65e290c6f Mon Sep 17 00:00:00 2001
From: Jesse Wright <63333554+jeswr@users.noreply.github.com>
Date: Sat, 4 Jul 2026 21:48:22 +0000
Subject: [PATCH] Pass exec/2 commands to the javascript host in the wasm
 version

In the wasm version there is no shell/2, so the graph scoped builtins
(log:collectAllIn, log:forAllIn, log:ifThenElseIn, log:conclusion,
log:satisfiable, e:call, e:fail and e:findall) could not spawn their
eye sub-reasoner. Following the userInput/2 precedent, exec/2 now
yields exec(Args, File) to the javascript host via await/2 under the
emscripten condition, where Args is the argv of the command and File
is the target of its stdout redirection.

See https://github.com/eyereasoner/eye-js/issues/873

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 eye.pl | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/eye.pl b/eye.pl
index a7fc75c62..f07a55085 100644
--- a/eye.pl
+++ b/eye.pl
@@ -12933,12 +12933,37 @@
     ),
     tmp_file(C, A).
 
+:- if(current_prolog_flag(emscripten, true)).
+% there is no shell in the wasm version so the command is passed to the
+% javascript host as exec(Args, File) via await/2, where Args is the argv
+% of the command and File is the target of its stdout redirection. The
+% host is expected to run the command, e.g. the eye sub-reasoner spawned
+% by the graph scoped builtins on a fresh wasm module, write the standard
+% output to File and answer "ok"
+exec(A, B) :-
+    atomic_list_concat(C, ' ', A),
+    findall(D,
+        (   member(D, C),
+            D \== ''
+        ),
+        E
+    ),
+    (   append(F, ['>', G|_], E)
+    ->  await(exec(F, G), H),
+        (   H == "ok"
+        ->  B = 0
+        ;   throw(exec_error(A))
+        )
+    ;   throw(exec_error(A))
+    ).
+:- else.
 exec(A, B) :-
     shell(A, B),
     (   B =:= 0
     ->  true
     ;   throw(exec_error(A))
     ).
+:- endif.
 
 getcwd(A) :-
     working_directory(A, A).