From 728b4f67dab3a5d4e8b03ebb9c5513bb005b1f7e Mon Sep 17 00:00:00 2001
From: hanez <you@hanez.org>
Date: Mon, 29 Sep 2025 18:22:40 +0200
Subject: [PATCH] Added a custom lib dir. E.g.: FUN_LIB_DIR="/some/dir\
 ./path/to/fun and added DEFAULT_LIB_DIR as compile time option.

---
 CMakeLists.txt     |  2 +-
 Makefile           |  8 ++++++++
 src/parser_utils.c | 39 +++++++++++++++++++++++++++++++++------
 3 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d3d193d..095dfdb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.16)
-project(fun VERSION 0.12.2 LANGUAGES C)
+project(fun VERSION 0.12.3 LANGUAGES C)
 
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_C_STANDARD_REQUIRED ON)
diff --git a/Makefile b/Makefile
index 2454352..8f426c8 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,14 @@ CMAKE ?= cmake
 # Default to a build with extra logging disabled
 CMAKE_FLAGS ?= -DFUN_DEBUG=OFF
 
+# Optional: override default library directory for #include <...> lookups
+# Usage: make DEFAULT_LIB_DIR=/custom/fun/lib
+# This injects a compiler define: -DDEFAULT_LIB_DIR="/custom/fun/lib/"
+ifneq ($(strip $(DEFAULT_LIB_DIR)),)
+CMAKE_FLAGS += -DCMAKE_C_FLAGS="$(CMAKE_C_FLAGS) -DDEFAULT_LIB_DIR=\\\"$(DEFAULT_LIB_DIR)/\\\""
+CMAKE_FLAGS += -DCMAKE_CXX_FLAGS="$(CMAKE_CXX_FLAGS) -DDEFAULT_LIB_DIR=\\\"$(DEFAULT_LIB_DIR)/\\\""
+endif
+
 .PHONY: all configure build fun fun_test test_opcodes clean distclean install repl run
 
 all: clean fun fun_test test_opcodes
diff --git a/src/parser_utils.c b/src/parser_utils.c
index 2b01fec..b0d1e2a 100644
--- a/src/parser_utils.c
+++ b/src/parser_utils.c
@@ -263,7 +263,12 @@ static char *preprocess_includes_internal(const char *src, int depth) {
         return strdup("");
     }
 
-    const char *LIB_DIR = "/usr/lib/fun/";
+    /* Build-time default, can be overridden by compiler define -DDEFAULT_LIB_DIR=".../" */
+    #ifndef DEFAULT_LIB_DIR
+    #define DEFAULT_LIB_DIR "/usr/lib/fun/"
+    #endif
+
+    const char *env_lib = getenv("FUN_LIB_DIR");
     size_t len = strlen(src);
     StrBuf out;
     sb_init(&out);
@@ -304,18 +309,40 @@ static char *preprocess_includes_internal(const char *src, int depth) {
                             while (k < len && src[k] != '\n') k++;
                             if (k < len && src[k] == '\n') k++;
 
-                            /* resolve file path */
+                            /* resolve file path; for <...> try FUN_LIB_DIR first, then default */
                             char resolved[1024];
+                            char resolved2[1024];
+                            size_t inc_len = 0;
+                            char *inc = NULL;
+
                             if (opener == '<') {
-                                snprintf(resolved, sizeof(resolved), "%s%s", LIB_DIR, path);
+                                /* Attempt environment override if provided */
+                                if (env_lib && env_lib[0]) {
+                                    size_t elen = strlen(env_lib);
+                                    int needs_slash = (elen > 0 && env_lib[elen - 1] != '/');
+                                    if (needs_slash)
+                                        snprintf(resolved, sizeof(resolved), "%s/%s", env_lib, path);
+                                    else
+                                        snprintf(resolved, sizeof(resolved), "%s%s", env_lib, path);
+                                    inc = read_file_all(resolved, &inc_len);
+                                }
+                                /* Fallback to default lib dir */
+                                if (!inc) {
+                                    snprintf(resolved2, sizeof(resolved2), "%s%s", DEFAULT_LIB_DIR, path);
+                                    inc = read_file_all(resolved2, &inc_len);
+                                    if (inc) {
+                                        /* reflect the actual resolved path in annotations */
+                                        strncpy(resolved, resolved2, sizeof(resolved) - 1);
+                                        resolved[sizeof(resolved) - 1] = '\0';
+                                    }
+                                }
                             } else {
+                                /* quoted include: relative path */
                                 snprintf(resolved, sizeof(resolved), "%s", path);
+                                inc = read_file_all(resolved, &inc_len);
                             }
                             free(path);
 
-                            /* read and recursively expand */
-                            size_t inc_len = 0;
-                            char *inc = read_file_all(resolved, &inc_len);
                             if (!inc) {
                                 fprintf(stderr, "Include error: cannot read '%s'\n", resolved);
                                 sb_append(&out, "// include error: cannot read ");