cpp scripting

README.md

want to write scripts in C++? sure you do.

put c-run in your path, then you can write scripts in C++ (or in C).

#!/usr/bin/env c-run
#include <iostream>
int main() {
    std::cout << "hello world\n";
}

and here is how it works...

$ hello-world.cpp
hello world

Note that running hello-world.cpp will compile the "script" the first time, and store it in ~/.cache/c-run. On subsequent invocation, c-run will check the timestamps and will not rebuild the "script" if it has not changed.

c-run

#!/bin/bash

# Input script from the command line
SCRIPT="$1"
[ -z "$SCRIPT" ] && { echo >&2 "no script given" ; exit 1 ; }

shift
ARGUMENTS=( "$@" )

# Directory to store compiled binaries
CACHE_DIR="$HOME/.cache/c-run"

# Ensure the cache directory exists
mkdir -p "$CACHE_DIR"

# Determine file extension and set the compiler
EXTENSION="${SCRIPT##*.}"
if [ "$EXTENSION" == "cpp" ]; then
    COMPILER="clang++ -std=c++20"
elif [ "$EXTENSION" == "c" ]; then
    COMPILER="clang -std=c17"
else
    echo >&2 "cannot determine compiler for $EXTENSION"
    exit 1
fi

# Remove the file extension to create a base name
BASENAME=$(basename "${SCRIPT%.*}")

# Compiled binary path
COMPILED="$CACHE_DIR/$BASENAME"

# Check if recompilation is needed (compile if source is newer than executable)
if [ "$SCRIPT" -nt "$COMPILED" ]; then
    # remove the first line
    FILTERED="$CACHE_DIR/$BASENAME.$EXTENSION"
    sed '1{/^#!/d}' <"$SCRIPT" >"$FILTERED"

    # Compile the file
    $COMPILER "$FILTERED" -o "$COMPILED"

    # Check if compilation was successful
    if [ $? -ne 0 ]; then
        echo "Compilation failed, not executing."
        exit 1
    fi
fi

# Execute the compiled binary
"$COMPILED" "${ARGUMENTS[@]}"