Peel off assemblers into optional module.

Not sufficiently tested.

esp32/README-optional.txt

@@ -0,0 +1,20 @@
++----------------------------------+
+|  ESP32forth - Optional Packages  |
++----------------------------------+
+
+ESPforth supports a number of optional packages, included in this directory.
+
+By default ESPforth will only include core functionality.
+To include one or more of these modules, move them from this directory
+into the parent directory, next to the ESPforth.ino file.
+
+These are the current optional modules:
+  * assemblers.h - Assemblers for ESP32 Xtensa and ESP32 RISC-V
+
+Initially ESP32forth focused on a minimal C kernel, with most functionality
+built in Forth code loaded at boot. Eventually, as support for more capabilities
+were added to ESPforth, this became unsustainable.
+
+Optional modules demonstrate good patterns for use in your own extensions
+to ESP32forth. You can add you own modules by #including them from
+an optional userwords.h file placed next to ESPforth.ino

esp32/README.txt

@@ -0,0 +1,20 @@
++--------------+
+|  ESP32forth  |
++--------------+
+
+This is ESP32forth v{{VERSION}} (Revision {{REVISION}}).
+
+ESP32forth is an indirect threaded Forth for the ESP32 family of microcontrollers.
+It uses a small C "kernel" that boots via inline Forth code.
+The use of C allows developers to leverage C/C++ ESP32 libraries with minimal effort.
+
+To compile and flash with the Arduino tools, load ESP32forth.ino.
+
+Documentation and the latest version of ESP32forth are available at:
+https://esp32forth.appspot.com/
+
+Full unexpanded source code and an issue tracker are available at:
+https://github.com/flagxor/ueforth
+
+There are several optional components that you can add into ESP32forth.
+See: optional/README-optional.txt

esp32/assemblers.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2023 Bradley D. Nelson
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+*/
+
+/*
+ * ESP32forth Assemblers v{{VERSION}}
+ * Revision: {{REVISION}}
+ */
+
+{{assemblers}}
+
+#define OPTIONAL_ASSEMBLERS_SUPPORT \
+  XV(internals, "assemblers-source", ASSEMBLERS_SOURCE, \
+      PUSH assemblers_source; PUSH sizeof(assemblers_source))

esp32/builtins.h

@@ -22,19 +22,27 @@
 # include <sys/stat.h>
 # include <sys/select.h>
 
-// Optional hook to pull in words for userwords.h
+// Hook to pull in words from optional userwords.h
 # if __has_include("userwords.h")
 #  include "userwords.h"
 # else
 #  define USER_WORDS
 # endif
 
+// Hook to pull in words from optional assemblers.h
+# if __has_include("assemblers.h")
+#  include "assemblers.h"
+# else
+#  define OPTIONAL_ASSEMBLERS_SUPPORT
+# endif
+
 static cell_t ResizeFile(cell_t fd, cell_t size);
 
 #endif
 
 #define PLATFORM_OPCODE_LIST \
   USER_WORDS \
+  OPTIONAL_ASSEMBLERS_SUPPORT \
   REQUIRED_PLATFORM_SUPPORT \
   REQUIRED_ESP_SUPPORT \
   REQUIRED_MEMORY_SUPPORT \

esp32/optionals.fs

@@ -0,0 +1,19 @@
+\ Copyright 2023 Bradley D. Nelson
+\
+\ Licensed under the Apache License, Version 2.0 (the "License");
+\ you may not use this file except in compliance with the License.
+\ You may obtain a copy of the License at
+\
+\     http://www.apache.org/licenses/LICENSE-2.0
+\
+\ Unless required by applicable law or agreed to in writing, software
+\ distributed under the License is distributed on an "AS IS" BASIS,
+\ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+\ See the License for the specific language governing permissions and
+\ limitations under the License.
+
+internals
+
+DEFINED? assemblers-source [IF] assemblers-source evaluate [THEN]
+
+forth

esp32/print-builtins.cpp

@@ -23,6 +23,7 @@
 #define CALLING_OPCODE_LIST
 #define FLOATING_POINT_LIST
 #define USER_WORDS
+#define OPTIONAL_ASSEMBLERS_SUPPORT
 #include "builtins.h"
 
 #define XV(flags, name, op, code) Z(flags, name, op, code)