C interpreter shell script

README.md

Shell script to interpret C

I use this script to run C snippets quickly on the commandline, for example to print constants, offsets, or sizes when working in other languages.

If you want to add it to a bin folder, it might be useful to add "$(basename "$0")" "$@" to the bottom and making symbolic links for each function.

csizeof.sh

#!/usr/bin/env bash

declare -a ceval_sh_tempfiles=( )
ceval_sh_cleanup() {
  if (( ${#ceval_sh_tempfiles[@]} )) then
    rm -rf -- "${ceval_sh_tempfiles[@]}"
  fi
}
trap ceval_sh_cleanup EXIT

ceval_sh_cc () {
  local out="$(mktemp)"
  ceval_sh_tempfiles+=("$out")
  "${CC:-cc}" "$@" - -o "$out"
  local cc_exit="$?"
  printf '%s' "$out"
  return "$cc_exit"
}

ceval () {
  if [[ "$#" -lt 1 ]]; then
    printf '%s\n' "Usage: $0 [-i <standard header list>] [-I <nonstandard header list>] <code | -> [program args...]" >&2
    printf '%s\n' "  where header list is a comma separated list of headers names, sans .h like: stdlib,stdbool"      >&2
    printf '%s\n' "  standard header format: <name.h>, nonstandard format: \"name.h\" (stdio is included by default)" >&2
    return 1
  fi
  local code_arg=""
  local -a includes=("<stdio.h>")
  while [[ "$#" -gt 0 ]]; do
    case "$1" in
      -i)
        if [[ "$#" -lt 2 ]]; then
          printf '%s\n' "option -i expects an argument" >&2
          return 1
        fi
        local item
        while IFS=, read -r item; do
          includes+=("<$item.h>")
        done <<< "$2"
        shift
        ;;
      -I)
        if [[ "$#" -lt 2 ]]; then
          printf '%s\n' "option -I expects an argument" >&2
          return 1
        fi
        local item
        while IFS=, read -r item; do
          includes+=("\"$item.h\"")
        done <<< "$2"
        shift
        ;;
      -)
        code_arg='-'
        shift
        break
        ;;
      --)
        # skip and go to positional arg parsing
        shift
        break
        ;;
      -*|--*)
        printf "unrecognized option: %s" "$1" >&2
        return 1
        ;;
      *)
        # go to positional arg parsing
        break
        ;;
    esac
    shift
  done
  if [[ -z "$code_arg" ]]; then
    if [[ "$#" -lt 1 ]]; then
      printf '%s\n' "expected positional code argument" >&2
      return 1
    fi
    code_arg="$1"
    shift
  fi

  #printf 'code_arg: %s\n' "$code_arg"
  #printf 'includes: '
  #printf '%s ' "${includes[@]}"
  #printf '\n'
  #printf 'program args: '
  #printf '%s ' "$@"
  #printf '\n'

  local code
  local exit
  if [[ "$code_arg" = '-' ]]; then
    code="$(cat -)"
    exit="$?"
    if [[ "$exit" -ne 0 ]]; then
      return "$exit"
    fi
  else
    code="$code_arg"
  fi

  # must separate the local and the assignment, because otherwise `local` will clobber
  #  $? with 0
  local out
  out="$( ( printf '#include %s\n' "${includes[@]}" &&
    printf 'int main(int argc, char **argv) {\n%s\n}' "$code" ) | tee /tmp/a.c | ceval_sh_cc -x c)"
  exit="$?"
  if [[ "$exit" -ne 0 ]]; then
    return "$exit"
  fi

  "$out" "$@"
  return "$?"
}

cprintf () {
  local -a args=( )
  while [[ "$#" -gt 0 ]]; do
    case "$1" in
      -i|-I)
        if [[ "$#" -lt 2 ]]; then
          printf 'option %s expects an argument\n' "$1" >&2
          return 1
        fi
        args+=("$1" "$2")
        shift
        ;;
      --)
        # record and go to positional arg parsing
        args+=("$1")
        shift
        break
        ;;
      -) 
        printf 'reading code from stdin is not supported by this command' >&2
        return 1
        ;;
      -*)
        # pass options on
        args+=("$1")
        ;;
      *)
        # go to positional arg parsing
        break
        ;;
    esac
    shift
  done
  
  if [[ "$#" -ne 2 ]]; then
    printf 'Usage: %s [options] <format specifier> <arguments>' "$0" >&2
    return 1
  fi

  local fmt="$1"
  shift
  local code="$( printf 'printf("%s"' "$fmt" && printf ', %s' "$@" && printf ');' )"

  ceval "${args[@]}" "$code"
  return "$?"
}

csizeof () {
  local -a args=( )
  while [[ "$#" -gt 0 ]]; do
    case "$1" in
      -i|-I)
        if [[ "$#" -lt 2 ]]; then
          printf 'option %s expects an argument\n' "$1" >&2
          return 1
        fi
        args+=("$1" "$2")
        shift
        ;;
      --)
        # record and go to positional arg parsing
        args+=("$1")
        shift
        break
        ;;
      -) 
        printf 'reading code from stdin is not supported by this command' >&2
        return 1
        ;;
      -*)
        # pass options on
        args+=("$1")
        ;;
      *)
        # go to positional arg parsing
        break
        ;;
    esac
    shift
  done

  if [[ "$#" -ne 1 ]]; then
    printf 'Usage: %s [options] <type>' "$0" >&2
  fi

  cprintf "${args[@]}" '%d\n' "sizeof($1)"
  return "$?"
}