Function _is_single_expression

src/specify_cli/workflows/expressions.py:149–183

True when *stripped* is exactly one top-level ``{{ ... }}`` block. Scans the block body for a ``}}`` that would close it early, ignoring any braces inside string literals. This keeps a lone expression whose string argument contains a literal ``{{`` or ``}}`` (e.g. ``{{ inputs.text |

(stripped: str)

def _is_single_expression(stripped: str) -> bool:
    """True when *stripped* is exactly one top-level ``{{ ... }}`` block.

    Scans the block body for a ``}}`` that would close it early, ignoring any
    braces inside string literals. This keeps a lone expression whose string
    argument contains a literal ``{{`` or ``}}`` (e.g.
    ``{{ inputs.text | contains('}}') }}``) on the typed fast path, while
    ``{{ a }} {{ b }}`` and ``{{ a }}{{ b }}`` are correctly seen as
    multi-expression. Mirrors the quote handling in
    ``_split_top_level_commas``.

    A regex span check cannot decide this: the pattern's non-greedy body stops
    at the first ``}}``, so a literal ``}}`` inside a string argument would be
    mistaken for the closing delimiter (issue #3208, follow-up review).
    """
    if not (stripped.startswith("{{") and stripped.endswith("}}")):
        return False
    inner = stripped[2:-2]
    if not inner.strip():
        return False
    quote: str | None = None
    i = 0
    n = len(inner)
    while i < n:
        ch = inner[i]
        if quote is not None:
            if ch == quote:
                quote = None
        elif ch in ("'", '"'):
            quote = ch
        elif ch == "}" and i + 1 < n and inner[i + 1] == "}":
            # A ``}}`` outside quotes closes the first block early.
            return False
        i += 1
    return True


def _split_top_level_commas(text: str) -> list[str]: