How to use the command ocamlfind (with examples)

The ocamlfind command is the findlib package manager for OCaml. It simplifies linking executables with external libraries.

Use case 1: Compile a source file to a native binary and link with packages

Code:

ocamlfind ocamlopt -package package1,package2 -linkpkg -o path/to/executable path/to/source.ml

Motivation: Compiling a source file to a native binary allows for faster execution and improved performance. Linking with specific packages ensures that the necessary libraries are included in the binary.

Explanation:

• ocamlfind: The main command for the ocamlfind package manager.
• ocamlopt: Specifies the OCaml compiler to be used for native code generation.
• -package package1,package2: Specifies the packages to be linked with the executable. Replace package1 and package2 with the actual names of the required packages.
• -linkpkg: Includes the linked packages in the final executable.
• -o path/to/executable: Specifies the output file path for the generated executable. Replace path/to/executable with the desired location and name of the executable.
• path/to/source.ml: Specifies the path to the source file to be compiled. Replace path/to/source.ml with the actual source file path.

Example output: The source file is compiled to a native binary and linked with the specified packages, generating an executable at the specified output path.

Use case 2: Compile a source file to a bytecode binary and link with packages

Code:

ocamlfind ocamlc -package package1,package2 -linkpkg -o path/to/executable path/to/source.ml

Motivation: Compiling to a bytecode binary allows for easier distribution as it can run on any platform with the same version of OCaml installed. Linking with packages ensures that the required libraries are included in the bytecode.

Explanation:

• ocamlfind: The main command for the ocamlfind package manager.
• ocamlc: Specifies the OCaml compiler to be used for bytecode generation.
• -package package1,package2: Specifies the packages to be linked with the executable. Replace package1 and package2 with the actual names of the required packages.
• -linkpkg: Includes the linked packages in the final executable.
• -o path/to/executable: Specifies the output file path for the generated executable. Replace path/to/executable with the desired location and name of the executable.
• path/to/source.ml: Specifies the path to the source file to be compiled. Replace path/to/source.ml with the actual source file path.

Example output: The source file is compiled to a bytecode binary and linked with the specified packages, generating an executable at the specified output path.

Use case 3: Cross-compile for a different platform

Code:

ocamlfind -toolchain cross-toolchain ocamlopt -o path/to/executable path/to/source.ml

Motivation: Cross-compiling allows for generating code that runs on a different platform than the one being used for compilation. This is useful, for example, when developing software for embedded systems or targeting specific architectures.

Explanation:

• ocamlfind: The main command for the ocamlfind package manager.
• -toolchain cross-toolchain: Specifies the cross-toolchain to be used for cross-compilation. Replace cross-toolchain with the actual toolchain name.
• ocamlopt: Specifies the OCaml compiler to be used for native code generation.
• -o path/to/executable: Specifies the output file path for the generated executable. Replace path/to/executable with the desired location and name of the executable.
• path/to/source.ml: Specifies the path to the source file to be compiled. Replace path/to/source.ml with the actual source file path.

Example output: The source file is cross-compiled using the specified cross-toolchain and generated an executable at the specified output path. The resulting executable can be run on the target platform.

Conclusion:

The ocamlfind command is a powerful package manager for OCaml that simplifies the process of linking executables with external libraries. Whether it’s compiling to a native or bytecode binary, or cross-compiling for a different platform, ocamlfind provides the necessary tools to streamline the development process.