Tutorial: Usage

The ucode command line utility provides a set of options and arguments for executing and compiling ucode programs. Here is a detailed explanation of each option and its usage:

-h: Display the help message, which provides an overview of the available options and their usage.
-e "expression": Execute the given expression as a ucode program. This option allows you to provide a single-line ucode expression for immediate execution.
-p "expression": Execute the given expression as a ucode program and print the result after execution.
-c [-s] [-o output.uc] input.uc [input2.uc ...]: Compile the specified source file(s) to bytecode instead of executing them. By default, the compiled bytecode is written to ./uc.out. The -s option omits debug information, reducing the size of the compiled bytecode. The -o option allows specifying the output file path for the compiled bytecode.
-t: Enable VM (Virtual Machine) execution tracing. This option enables tracing of the ucode program's execution, providing detailed information for debugging purposes.
-g interval: Perform periodic garbage collection at regular intervals defined by the interval parameter. Garbage collection is a memory management process that frees up memory occupied by objects that are no longer in use.
-S: Enable strict mode, which enforces strict adherence to ucode language rules and prevents the use of certain potentially error-prone or unsafe language features.
-R: Process source file(s) as raw script code. This is the default mode of operation, where the ucode interpreter treats the source files as direct ucode script code.
-T[flag,flag,...]: Process the source file(s) as templates instead of raw script code. This option enables the usage of Jinja-like templates with embedded ECMAScript 6 code. The flags provide additional control over template processing, such as preserving leading whitespace or trailing newlines.
-D [name=]value: Define a global variable in the ucode program. If the name parameter is omitted, a JSON dictionary is expected as the value, where each property becomes a global variable with its corresponding value. If name is specified, it defines a global variable with the provided value, parsed as JSON or as a literal string if JSON parsing fails.
-F [name=]path: Similar to the -D option, but reads the value from a file specified by the path parameter. The file must contain a single, well-formed JSON dictionary.
-U name: Undefine the given global variable name. This option removes the specified global variable from the ucode program's scope.
-l [name=]library: Preload the specified library for use in the ucode program. Optionally, the library can be aliased to a different name within the program.
-L pattern: Prepend the provided pattern to the default library search paths. This option allows specifying custom paths for loading libraries. If the pattern does not contain an asterisk (*), it is added twice, once with /*.so and once with /*.uc appended to it.

Examples

Here are some examples showcasing the invocation of the ucode program with different options:

Execute a ucode expression:
```
ucode -e "print('Hello, World!\n');"
```
Execute a ucode expression and print the result:
```
ucode -p "2 ** 3"
```
Execute a ucode program from a source file:
```
ucode program.uc
```
Compile a ucode program to bytecode:
```
ucode -c program.uc
```
Compile a ucode program to bytecode with a specified output file:
```
ucode -c -o compiled.uc program.uc
```