Markdown Table Formatter CLI

Project roadmap

1. 01

   Read the input

   ~1h

   Write mdtable.rb that reads from a file given as an argument, or from standard input when none is given (ARGF does both). Parse it with the csv library using the delimiter from --delimiter (comma by default, or tab with --tsv), so quoted fields with commas work. Skip empty lines and report a clear error for empty input. Done when: the tool reads a CSV file and a piped TSV into an array of rows.

2. 02

   Compute column widths

   ~1h

   Make every row the same length (padding short rows with empty cells, and warning about them), escape | as \| and turn line breaks inside cells into spaces, then compute each column's width as the longest cell in that column (at least 3, for the separator). Use the display length of strings, so accented letters count as one character. Done when: widths are correct for a sample with different cell lengths.

3. 03

   Render the table

   ~1h

   Print the header row, the separator row (dashes with colons for alignment: :--- left, :---: center and ---: right, from an --align option such as l,c,r), and the data rows, with each cell padded to its column width (ljust, center or rjust to match the alignment). Done when: the output renders as a correct table on GitHub and looks aligned as plain text.

4. 04

   Add options

   ~1h

   Use OptionParser for --delimiter, --tsv, --align, --no-header (generating Column 1, Column 2 headers) and --output FILE (writing to standard output by default). Show usage with --help and for invalid options. Done when: every option works, and invalid ones print the usage.

5. 05

   Test it

   ~1h

   Write Minitest tests: quoted fields with commas, pipes in cells, uneven rows, each alignment, --no-header, accented text widths, and empty input. Done when: the tests pass.

Resources

• DocsRuby documentation: CSV
• DocsRuby documentation: ARGF
• DocsRuby documentation: String
• DocsGitHub Flavored Markdown: tables
• DocsRuby documentation: OptionParser