Native Ledger Summarizer

Transforms purchase lines into aggregated totals using native runtime types and standard exception semantics.

Capabilities

Normalize entries

• Input lines ["coffee,3", "bagel,2", "coffee,-1"] produce a mapping with exactly two keys: coffee totals 2 and bagel totals 2. @test
• Encountering a line without the comma delimiter (e.g., "brokenline") aborts processing and raises a built-in exception for malformed input. @test

Enforce integer amounts

• If an amount token is not an integer (e.g., "tea,2.5"), raise the built-in exception associated with invalid numeric conversion. @test

Lookup totals safely

• Requesting a total for a category that is not present in the normalized summary raises the native missing-key exception. @test

Validate input type

• Passing a non-iterable input such as None raises the built-in type-mismatch exception before any parsing is attempted. @test

Implementation

@generates

API

from typing import Iterable, Mapping

def normalize_entries(lines: Iterable[str]) -> Mapping[str, int]:
    """Parse comma-delimited lines of <category>,<integer amount> into aggregated totals using native mapping and integer primitives."""


def category_total(summary: Mapping[str, int], category: str) -> int:
    """Return the total for the requested category from a normalized summary or raise the native missing-key exception."""

Dependencies { .dependencies }

Python built-ins { .dependency }

Native runtime types for sequences/mappings, conversion helpers, and standard exception hierarchy.