Code snippets for "Adventures in Language Design" blog entry

block_example.rb

# Explicitly opens and closes the file
def read_file1(filename)
  file = nil

  begin
    file = File.open('somefile.txt')

    return file.readlines
  ensure
    file.close
  end
end

# Explicitly opens, but implicitly closes the
# file at the end of the block
def read_file2(filename)
  File.open('somefile.txt') { |file| file.readlines }
end

divisible_by_two.rb

def divisible_by_two(arr)
  arr.select { |value| value % 2 == 0 }
end

divisibleByTwo.c

int *divisibleByTwo(int *arr, int n)
{
    int *values;
    int count;

    /* snip C memory allocation crap */

    count = 0;
    for (int i = 0; i < n; ++i)
    {
        if (arr[i] % 2 == 0)
        {
            values[count++] = arr[i];
        }
    }

    /* snip C memory reallocation crap */

    return values;
}

divisibleByTwo.cpp

std::vector<int> divisibleByTwo(std::vector<int> arr)
{
    std::vector<int> values(arr.size());

    auto it = std::copy_if(arr.begin(),
                           arr.end(),
                           values.begin(),
                           [](int i){return i % 2 == 0;} );
    // snip C++ memory reallocation crap

    return values;
}

exceptionHandling.c

ERROR_CODE mungeData(size_t size,
                     char *inputFilename,
                     char *outputFilename)
{
    int *bar;

    CHECK_ALLOC(bar = malloc(size));
    CHECK_ERR(readDataFromFile(inputFilename, bar));
    CHECK_ERR(updateData(bar));
    CHECK_ERR(writeDataToFile(outputFilename, bar));
    free(bar):
    goto success;

error:
    free(bar);
    return errorCode; /* Set by the CHECK_ERR macro */

success:
    return SUCCESS;
}