Initial dataframe implementation #25

HEL · 2026-07-01T08:24:20Z

HEL commented

2026-07-01 08:24:20 +00:00

This PR adds some support for type checking dataframes and their columns. More precisely, it allows type checking their schema (and generating assertions on it), column access by name (single or multi) and column assignment by name (single or multi)
For example:

df: Frame[name: str, age: int] = ...
names = df["name"]  # <- type checked as Column[str]
df[["name", "age"]] = df[["age", "name"]]  # <- invalid because the types are wrong

The add operation is partially implemented on DataFrames

It also adds support for tuples, methods on str, multi-parameter generic application in Python, minor fixes, and it loosens some diagnostics from errors to warnings

This PR adds some support for type checking dataframes and their columns. More precisely, it allows type checking their schema (and generating assertions on it), column access by name (single or multi) and column assignment by name (single or multi) For example: ```python df: Frame[name: str, age: int] = ... names = df["name"] # <- type checked as Column[str] df[["name", "age"]] = df[["age", "name"]] # <- invalid because the types are wrong ``` The `add` operation is partially implemented on DataFrames It also adds support for tuples, methods on `str`, multi-parameter generic application in Python, minor fixes, and it loosens some diagnostics from errors to warnings

HEL self-assigned this 2026-07-01 08:24:20 +00:00

HEL added 39 commits 2026-07-01 08:24:20 +00:00

feat(types): add DataFrameType and ColumnType 556765fd35

fix(types): add str methods to dataframe types 5357ca8e58

feat(types): add TupleType 0d20993f02

feat(checker): type check subscript on dataframes a31d295eb1

feat(checker): handle setting dataframe column c91b206791

feat(gen): add support for tuples and dataframes 87d5e286d2

feat(parser): add frame type to midas syntax ede7272c09

feat(cli): add frame type to highlighter 7074b074bc

feat(checker): process frame type definitions cdf1725c26

feat(cli): print context for multiline diagnostics 7219109e5d