feat: implement markdown table parser with comprehensive test suite

src/markdown_table_parser.py

@@ -0,0 +1,130 @@
+\
+import re
+
+def parse_markdown_table(markdown_text: str) -> dict[str, list[str]] | None:
+    """
+    Parses the first valid Markdown table found in a string.
+    Returns a dictionary (headers as keys, lists of cell content as values)
+    or None if no valid table is found.
+    """
+    lines = [line.rstrip() for line in markdown_text.split('\n') if line.strip()]
+    n = len(lines)
+    i = 0
+    while i < n - 1:
+        header_line = lines[i].strip()
+        sep_line = lines[i+1].strip()
+        # Header and separator must start and end with |
+        if not (header_line.startswith('|') and header_line.endswith('|')):
+            i += 1
+            continue
+        if not (sep_line.startswith('|') and sep_line.endswith('|')):
+            i += 1
+            continue
+        # Split header and separator
+        headers = [h.strip() for h in header_line.strip('|').split('|')]
+        seps = [s.strip() for s in sep_line.strip('|').split('|')]
+        if len(headers) != len(seps):
+            i += 1
+            continue
+        # Separator must have at least one '-' in each cell, and only -, :, or spaces
+        valid_sep = all('-' in s and all(c in '-: ' for c in s) for s in seps)
+        if not valid_sep:
+            i += 1
+            continue
+        # Found a table, now parse data rows
+        # Special handling: if the first header is a row label (e.g., '*'), treat first cell of each row as row label, not data
+        has_row_labels = headers[0] not in ('',)
+        table = {h: [] for h in headers}
+        j = i + 2
+        while j < n:
+            row = lines[j].strip()
+            if not (row.startswith('|') and row.endswith('|')):
+                break
+            cells = [c.strip() for c in row.strip('|').split('|')]
+            if len(cells) != len(headers):
+                j += 1
+                continue
+            if has_row_labels and len(headers) > 1:
+                # First cell is row label, rest are data
+                table[headers[0]].append(cells[0])
+                for k, h in enumerate(headers[1:], 1):
+                    table[h].append(cells[k])
+            else:
+                for k, h in enumerate(headers):
+                    table[h].append(cells[k])
+            j += 1
+        return table
+    return None
+
+if __name__ == '__main__':
+    example_table = """
+    |*|a|b|c|d|e|
+    |---|---|---|---|---|---|
+    |a|a|b|c|b|d|
+    |b|b|c|a|e|c|
+    |c|c|a|b|b|a|
+    |d|b|e|b|e|d|
+    |e|d|b|a|d|c|
+    """
+    parsed = parse_markdown_table(example_table)
+    print("Parsed GAIA example:")
+    if parsed:
+        for header, column_data in parsed.items():
+            print(f"Header: {header}, Data: {column_data}")
+    else:
+        print("Failed to parse table.")
+
+    example_table_2 = """
+    Some text before
+    | Name  | Age | City      |
+    |-------|-----|-----------|
+    | Alice | 30  | New York  |
+    | Bob   | 24  | Paris     |
+    | Carol | 45  | London    |
+    Some text after
+    """
+    parsed_2 = parse_markdown_table(example_table_2)
+    print("\\nParsed Table 2 (with surrounding text):")
+    if parsed_2:
+        for header, column_data in parsed_2.items():
+            print(f"Header: {header}, Data: {column_data}")
+    else:
+        print("Failed to parse table 2.")
+
+    empty_table_with_header = """
+    | Header1 | Header2 |
+    |---------|---------|
+    """
+    parsed_empty = parse_markdown_table(empty_table_with_header)
+    print("\\nParsed Empty Table with Header:")
+    if parsed_empty:
+        for header, column_data in parsed_empty.items():
+            print(f"Header: {header}, Data: {column_data}")
+    else:
+        print("Failed to parse empty table with header.")
+    
+    malformed_separator = """
+    | Header1 | Header2 |
+    |---foo---|---------|
+    | data1   | data2   |
+    """
+    parsed_mal_sep = parse_markdown_table(malformed_separator)
+    print("\\nParsed table with malformed separator:")
+    if parsed_mal_sep:
+        print(parsed_mal_sep)
+    else:
+        print("Failed to parse (correctly).")
+
+    table_with_alignment = """
+    | Syntax    | Description |
+    | :-------- | :-----------: |
+    | Header    | Title       |
+    | Paragraph | Text        |
+    """
+    parsed_align = parse_markdown_table(table_with_alignment)
+    print("\\nParsed table with alignment in separator:")
+    if parsed_align:
+        for header, column_data in parsed_align.items():
+            print(f"Header: {header}, Data: {column_data}")
+    else:
+        print("Failed to parse table with alignment.")

tests/test_markdown_table_parser.py

@@ -0,0 +1,131 @@
+import pytest
+from src.markdown_table_parser import parse_markdown_table
+
+def test_simple_table():
+    md_table = """
+    | Name  | Age | City      |
+    |-------|-----|-----------|
+    | Alice | 30  | New York  |
+    | Bob   | 24  | Paris     |
+    """
+    expected = {
+        'Name': ['Alice', 'Bob'],
+        'Age': ['30', '24'],
+        'City': ['New York', 'Paris']
+    }
+    assert parse_markdown_table(md_table) == expected
+
+def test_gaia_question_table():
+    md_table = """
+    |*|a|b|c|d|e|
+    |---|---|---|---|---|---|
+    |a|a|b|c|b|d|
+    |b|b|c|a|e|c|
+    |c|c|a|b|b|a|
+    |d|b|e|b|e|d|
+    |e|d|b|a|d|c|
+    """
+    expected = {
+        '*': ['a', 'b', 'c', 'd', 'e'],
+        'a': ['a', 'b', 'c', 'b', 'd'],
+        'b': ['b', 'c', 'a', 'e', 'b'],
+        'c': ['c', 'a', 'b', 'b', 'a'],
+        'd': ['b', 'e', 'b', 'e', 'd'],
+        'e': ['d', 'c', 'a', 'd', 'c']
+    }
+    assert parse_markdown_table(md_table) == expected
+
+def test_table_with_empty_cells():
+    md_table = """
+    | Header1 | Header2 | Header3 |
+    |---------|---------|---------|
+    | A       |         | C       |
+    | D       | E       |         |
+    """
+    expected = {
+        'Header1': ['A', 'D'],
+        'Header2': ['', 'E'],
+        'Header3': ['C', '']
+    }
+    assert parse_markdown_table(md_table) == expected
+
+def test_no_data_rows():
+    md_table = """
+    | Col1 | Col2 |
+    |------|------|
+    """
+    expected = {
+        'Col1': [],
+        'Col2': []
+    }
+    assert parse_markdown_table(md_table) == expected
+
+def test_malformed_table_missing_separator():
+    md_table = """
+    | HeaderA | HeaderB |
+    | Val1    | Val2    |
+    """
+    assert parse_markdown_table(md_table) is None
+
+def test_malformed_table_column_mismatch():
+    md_table = """
+    | H1 | H2 |
+    |----|----|
+    | C1 | C2 | C3 |
+    """
+    # Current implementation skips rows with mismatched column counts
+    expected = {
+        'H1': [],
+        'H2': []
+    }
+    assert parse_markdown_table(md_table) == expected
+
+def test_not_a_table():
+    text = "This is just some plain text, not a table."
+    assert parse_markdown_table(text) is None
+
+def test_empty_string():
+    assert parse_markdown_table("") is None
+
+def test_table_with_extra_spacing():
+    md_table = """
+    |  Name   |  Age  |  City       |
+    |---------|-------|-------------|
+    |  Alice  |  30   |  New York   |
+    |  Bob    |  24   |  Paris      |
+    """
+    expected = {
+        'Name': ['Alice', 'Bob'],
+        'Age': ['30', '24'],
+        'City': ['New York', 'Paris']
+    }
+    assert parse_markdown_table(md_table) == expected
+
+def test_table_in_larger_text():
+    text_with_table = """
+    Some text before the table.
+    | Key | Value |
+    |-----|-------|
+    | K1  | V1    |
+    | K2  | V2    |
+    Some text after the table.
+    """
+    expected = {
+        'Key': ['K1', 'K2'],
+        'Value': ['V1', 'V2']
+    }
+    assert parse_markdown_table(text_with_table) == expected
+
+def test_table_with_different_separator_styles():
+    md_table = """
+    | Syntax    | Description |
+    | :-------- | :-----------: |
+    | Header    | Title       |
+    | Paragraph | Text        |
+    """
+    expected = {
+        'Syntax': ['Header', 'Paragraph'],
+        'Description': ['Title', 'Text']
+    }
+    assert parse_markdown_table(md_table) == expected
+