CLI Improvements

[antfu]

This PR rewrites CLI using commander.js

CLI Options

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WENYAN LANG 文言 Compiler v0.0.2

Usage: wenyan [options] [files...]

Options:
  -v, --version        Output the version
  -l, --lang <lang>    Target language, can be "js", "py" or "rb" (default: "js")
  -c, --compile        Output the compiled code instead of executing it
  -e, --eval <code>    Evaluate script
  -i, --interactive    Interactive REPL
  -o, --output [file]  Output compiled code or executing result to file
  -r, --render         Outputs renderings
  --roman              Romanize identifiers
  --log <file>         Save log to file
  --title <title>      Override title in rendering
  -h, --help           Display help

Changes

• Default to executing mode instead of compiling, refer to CLI improvements #353
• Make "flag" options not requiring values. (previous --exec=somehing makes no sense, all its need is --exec)
• --help option added
• The value of --output is optional

wenyan helloworld.wy --compile
# Output to console

wenyan helloworld.wy --compile --output
# Output to helloworld.js (same name as the input)

wenyan helloworld.wy --compile --output a.js
# Output to a.js

• Separate --render and --title. IMO, --render=圖靈機 is not very intuitive. Now please use

wenyan turing.wy --render --title=圖靈機

wenyan turing.wy --render
# the title will be the filename "turing"

• Make -r shorthand for --render instead of --roman

[LingDong-]

Looks great, thanks!