README

Language Implementation

What It Is. This Pascal implementation is a traditional, Pascal compiler tool suite with many enhancement for compatibility with modern Pascal usage. The tool suit include a compiler, optimizer, linker, lister, and run-time package. It targets a 16-bit, emulated stack machine that is implemented as a virtual machine by the run-time logic.

Refer to the PascalNotes.md file in the docs sub-directory for more language-oriented discussion.

What It Is Not. This Pascal Implementation would not be the best choice for desk-top application; it does not have a feature set that is as rich as other desk-top Pascal tool suites. It's virtual machine would probably not be optimal for the desk-top environement. But neither is it a tiny, minimal Pascal tool set. Although traditional and not object-based, it is a rather comple Pascal implementation suitable for significant developments.

Embedded Pascal. The environment where the Pascal compiler would be a good choice would probably be the embedded environment. The run-time builds on the standard C library and expects little more from the hardware platform. An RTOS environment or, perhaps, even a bare-metal environment would be a good fit. A port to NuttX is provided.

Configuring Pascal

The Pascal configuration is based on kconfig-frontends tools extracted from the Linux kernel. As of this writing, there is no officially maintainer for these tools. The kconfig-frontends are often available as an installable package under Linx distrubitions. A source snapshot and build instructions are avaiable at https://bitbucket.org/nuttx/tools/src/master/

$ cd *pascal-directory*
$ make menuconfig

Building Pascal Under Linux

The build system has been well excercised under a GNU development environment, in particular, the Cygwin environment. Because it is the same GNU environment, Linux should also build with no issues. No attempt has been made to verify the build under BSD environments (including macOS).

$ cd *pascal-directory*
$ make

Building Pascal Under NuttX

NuttX is a mature, open-source RTOS that runs on many MCUs. When building for NuttX, you need to cross compile the code on a host machine. Code under tools/, for example must always build in the host environment. And the run-time code must always be built for the target MCU environment. It is an option whether you want to host the build tools (compiler, optimizer, linker, lister, etc) on the host cross-development environment or on the target itself.

1. Before configuring NuttX, create a symbolic link to the Pascal root directory in the NuttX apps directory:

   $ cd nuttx-apps-directory $ ln -s pascal-directory pascal

2. Then configure NuttX using the board board configuration of your choice. Make sure to enable Pascal support in the Application Configuration menu.

   $ cd nuttx-directory $ make menuconfig

   The most important decision to make in the configuration is if you want to host the entire Pascal development toolchain on the target. That does not require as much memory as you might think, but neither is it for the memory-limited embedded platform.

   The run-time alone has value because you can code, compile, and link Pascal programs on the host, then run them on the target.

3. And make in the nuttx-directory

   $ cd nuttx-directory $ make

And you should have the Pascal components that you have selected in your board's flash image.

Tips:

• Select the NuttX readline() function with CONFIG_SYSTEM_READLINE=y. By default fgets is used and the NuttX fgets does not behave in the expected way.