The Minecraft command parser

This project is a parser for Minecraft Bedrock command, which supports:

• syntax highlighting
• error reporting
• auto-completing with:
  • hints for every branch that explain the usages
  • ID hints (e.g. item ID and entity ID)
  • localization support (i.e. hint in different languages)
• different versions of command system (from 1.19.0 to 1.20.60!)

These almost make an IDE for command! Use Python (3.6+) to run main.py and try the "IDE" we make.

Flexible interface

This project uses a very flexible algorithm to make it easy to create syntax rules. Take this syntax as an example:

foo spam <bar: int> [ham: bool]
foo spam <bar: int>L <victim: target>
foo eggs <honey|chocolate|boston_cream> [store: pos]

The parsing tree will be like:

from mccmdhl2 import *
from mccmdhl2.nodes import *

tree = (Keyword("foo")  # A literal word "foo"
  .branch(Keyword("spam")
    .branch(Integer()  # An integer
      .branch(Boolean()
        .finish(EOL)  # End of line
      )
      .branch(Keyword("L")
        .branch(Selector()
          .finish(EOL)
        ),
        is_close=True  # No space between integer and "L"
      )
      .finish(EOL)  # The "ham: bool" is optional
    )
  )
  .branch(Keyword("eggs")  # The other "eggs" branch
    .branch(Enumerate(
      "honey", "chocolate", "boston_cream"
    )  # One of the 3 choices
      .branch(Pos3D()  # Position
        .finish(EOL)
      )
      .finish(EOL)
    )
  )
)

Then use the tree to parse a source:

test_src = """\
foo eggs boston_cream 10.2 ~-1~.5
foo eggs honey
foo spam 1 true
foo spam 3L @p[c=0, scores={money=5..}]
foo eggs vanilla_dip"""  # Last 2 lines have mistakes
parser = MCCmdParser(test_src, tree)
while not parser.is_finish():
    try:
        parser.parse_line()
    except BaseError as err:
        print("Error: %s" % parser.resolve_error(err))

# Highlight information
print("===== Highlighting =====")
for mark in parser.get_font_marks():
    print(mark)

Output:

Error: 4:18~4:19: Number can't be 0
Error: 5:9: Expect one of ('honey', 'chocolate', 'boston_cream')
===== Highlighting =====
<FontMark <Ln 1 Col 1>~<Ln 1 Col 4> keyword>
<FontMark <Ln 1 Col 5>~<Ln 1 Col 9> keyword>
<FontMark <Ln 1 Col 10>~<Ln 1 Col 22> keyword>
<FontMark <Ln 1 Col 23>~<Ln 1 Col 27> position>
...

To let it adapt to the auto-completing system (with the hint for every branch), check out the .note method we call in mccmdhl2/nodes.py and the translation system (mccmdhl2/translator.py and mccmdhl2/res/translation.json).

Why mccmdhl2?

Why is the package named mccmdhl2?

mc is the short name of Minecraft. cmd is the short form of command. hl means highlighter. mccmdhl is actually the package name of my old project which is also a command parser. It used a different algorithm and this project is here to replace that one. Therefore, we add a 2 to indicate that this is a completely re-written one.

Acknowledgement

Big, big thanks to @missing244, for:

• giving me ideas on optimizing my algorithm
• helping improving performance of the program
• discovering and reproducing those annoying UI-related bugs for me
• always listening to me patiently and supporting me