SIMPLE_PROCESS

Documentation

Process Execution Library for Eiffel

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Overview

SIMPLE_PROCESS provides SCOOP-compatible process execution for Eiffel applications. It wraps Win32 Process APIs through a clean C interface, enabling command execution with output capture without threading complications.

Important: This library has no dependency on the EiffelStudio process library. It uses direct Win32 API calls through a custom C wrapper, making it fully SCOOP-compatible and eliminating threading issues that existed with the previous Eiffel process library dependency.

Developed using AI-assisted methodology: Built interactively with Claude Opus 4.5 following rigorous Design by Contract principles.

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Features

Process Operations

• Execute Commands - Run shell commands and capture output
• Working Directory - Execute in specific directories
• Output Capture - Get stdout as STRING_32
• Exit Codes - Access process exit codes
• Error Handling - Detailed error messages on failure
• PATH Lookup - Check if executables exist in PATH
• Window Visibility - Show/hide process windows

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Quick Start

Installation

1. Clone the repository:

git clone https://github.com/simple-eiffel/simple_process.git

2. Compile the C library:

cd simple_process/Clib
compile.bat

3. Set the environment variable:

set SIMPLE_PROCESS=D:\path\to\simple_process

4. Add to your ECF file:

<library name="simple_process" location="$SIMPLE_PROCESS\simple_process.ecf"/>

Basic Usage

class
    MY_APPLICATION

feature

    process_example
        local
            proc: SIMPLE_PROCESS
            output: STRING_32
        do
            create proc.make

            -- Execute command and get output
            output := proc.output_of_command ("cmd /c dir")
            print (output)

            -- Check result
            if proc.was_successful then
                print ("Exit code: " + proc.last_exit_code.out + "%N")
            else
                if attached proc.last_error as err then
                    print ("Error: " + err + "%N")
                end
            end

            -- Execute in specific directory
            output := proc.output_of_command_in_directory ("cmd /c dir", "C:\Windows")
            print (output)

            -- Check if executable exists in PATH
            if proc.file_exists_in_path ("git.exe") then
                print ("Git is installed%N")
            end

            -- Show process window (default is hidden)
            proc.set_show_window (True)
            proc.execute ("notepad.exe")
        end

end

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API Reference

SIMPLE_PROCESS Class

Creation

make
    -- Initialize process executor.

Execution

execute (a_command: READABLE_STRING_GENERAL)
    -- Execute `a_command' and capture output.

execute_in_directory (a_command: READABLE_STRING_GENERAL; a_directory: detachable READABLE_STRING_GENERAL)
    -- Execute `a_command' in `a_directory' and capture output.

output_of_command (a_command: READABLE_STRING_GENERAL): STRING_32
    -- Execute `a_command' and return output.

output_of_command_in_directory (a_command: READABLE_STRING_GENERAL; a_directory: READABLE_STRING_GENERAL): STRING_32
    -- Execute `a_command' in `a_directory' and return output.

Results

last_output: detachable STRING_32
    -- Output from last command execution.

last_exit_code: INTEGER
    -- Exit code from last command execution.

last_error: detachable STRING_32
    -- Error message if execution failed.

was_successful: BOOLEAN
    -- Was last execution successful?

Settings

show_window: BOOLEAN
    -- Show process window during execution?

set_show_window (a_value: BOOLEAN)
    -- Set whether to show process window.

Query

file_exists_in_path (a_filename: READABLE_STRING_GENERAL): BOOLEAN
    -- Does `a_filename' exist in system PATH?

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Building & Testing

Build Library

cd simple_process
ec -config simple_process.ecf -target simple_process -c_compile

Run Tests

ec -config simple_process.ecf -target simple_process_tests -c_compile
./EIFGENs/simple_process_tests/W_code/simple_process.exe

Test Results: 9 tests passing

Tests cover:

• Command execution
• Output capture
• Exit code retrieval
• Directory execution
• PATH checking
• Window visibility settings
• Error handling

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Project Structure

simple_process/
├── Clib/                       # C wrapper library
│   ├── simple_process.h        # C header file
│   ├── simple_process.c        # C implementation
│   └── compile.bat             # Build script
├── src/                        # Eiffel source
│   ├── simple_process.e        # Main process class
│   └── simple_process_helper.e # Legacy helper class
├── testing/                    # Test suite
│   ├── application.e           # Test runner
│   └── test_simple_process.e   # Test cases
├── simple_process.ecf          # Library configuration
├── README.md                   # This file
└── LICENSE                     # MIT License

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Migration from Previous Version

If you were using the previous version that depended on the EiffelStudio process library:

Old (Thread-dependent)

-- Required thread concurrency mode
-- Used PROCESS_FACTORY and BASE_PROCESS

New (SCOOP-compatible)

-- Uses direct Win32 API calls
-- No thread dependencies
-- Cleaner, simpler API
local
    proc: SIMPLE_PROCESS
do
    create proc.make
    proc.execute ("my_command")
end

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Dependencies

• Windows OS - Process API is Windows-specific
• EiffelStudio 23.09+ - Development environment
• Visual Studio C++ Build Tools - For compiling C wrapper

No EiffelStudio process library dependency - This library uses its own C wrapper for all process operations.

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SCOOP Compatibility

SIMPLE_PROCESS is fully SCOOP-compatible. The C wrapper handles all Win32 API calls synchronously without threading dependencies, making it safe for use in concurrent Eiffel applications.

This is a key improvement over the previous version which required thread concurrency mode due to its dependency on the EiffelStudio process library.

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License

MIT License - see LICENSE file for details.

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Contact

• Author: Larry Rix
• Repository: https://github.com/simple-eiffel/simple_process
• Issues: https://github.com/simple-eiffel/simple_process/issues

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Acknowledgments

• Built with Claude Opus 4.5 (Anthropic)
• Uses Win32 Process APIs (Microsoft)
• Part of the simple_ library collection for Eiffel