Python API#

def to_spec(spec: str | Path | Mapping[str, object] | Spec) -> Spec:
    """Load and validate a spec definition — the language's front door.

    Everything decidable without data is decided here: schema shape, every
    rule one declaration is held to against the others, every expression and
    where string, and every macro template.

    Args:
        spec: A YAML path — a [`Path`][], or a ``str`` with no
            newline in it — the YAML text itself as a ``str`` with one, a
            mapping, or a loaded [`Spec`][].

    Returns:
        The schema *as the file declares it*, ``piecewise:`` intact.

    Raises:
        LanguageError: Anything the language does not accept, a text that is
            not a mapping of sections included.
        FileNotFoundError: A ``str`` with no newline that names no file.
    """
    if isinstance(spec, (list, tuple)):
        msg = 'a spec is one file, one dict or one Spec, never a list of them; merge the declarations into one dict.'
        raise SchemaError(msg)
    if isinstance(spec, Spec):
        return spec
    return Spec.model_validate(spec if isinstance(spec, Mapping) else read_spec(spec))

def merge(fragments: Sequence[Source], description: str | None = None) -> Spec:
    """*fragments* composed as peers, each owning the math it declares.

    Args:
        fragments: Each fragment as a YAML path, YAML text, a mapping, or a
            loaded [`Spec`][mathspec.spec.Spec]. A sum and the objective write
            their terms in the order of the list.
        description: What the composed spec is. A fragment's own
            ``description`` is about the fragment, and is not carried.

    Returns:
        The composed spec, loaded. A given declaration a sibling introduces is
        folded away; one nothing introduces stays under ``given:``.

    Raises:
        LanguageError: A fragment does not load on its own; two fragments
            declare one name; two fragments say different things about one
            dimension, relation or given declaration; a fragment reads a name as
            something other than what its sibling introduces, as another kind
            of thing, or over fewer dimensions than its body carries; a fragment
            adds a term to a variable, a parameter, a constraint or a
            definition written as ``cases:``; a term reads its own sum through
            another fragment; a name no fragment defines is read by nothing
            but the fragments that add a term to it, or by one fragment alone;
            the readers of such a name write its dims in different orders; two
            fragments are written against different language versions; their
            objectives run opposite ways; or the composed spec does not load.
        FileNotFoundError: A ``str`` with no newline that names no file.
        TypeError: *fragments* is one path rather than a list.
    """
    loaded = {name: _fragment(name, fragment) for name, fragment in _labelled(fragments, 'fragments').items()}
    read = {name: spec.to_dict() for name, spec in loaded.items()}
    merged: dict[str, object] = {'version': _one_version(read)}
    if description is not None:
        merged['description'] = description
    for section in SHARED_SECTIONS:
        if agreed := _agreed(read, section, _singular(section), 'give one of them a name of its own'):
            merged[section] = agreed
    asked = {name: spec.given.model_dump(exclude_unset=True) for name, spec in loaded.items()}
    readings = {
        kind: _agreed(asked, kind, label, 'read it over one frame', claims=_reading_claims)
        for kind, label in GIVEN_KINDS.items()
    }
    for section in OWNED_SECTIONS:
        if claimed := _claimed(read, section):
            merged[section] = claimed
    summed = _summed(loaded, merged, readings['expressions'], read)
    if expressions := {**_mapping(merged.get('expressions')), **summed}:
        merged['expressions'] = {key: _without(block, 'adds_to') for key, block in expressions.items()}
    if given := _folded(read, merged, loaded, readings):
        merged['given'] = given
    if (objective := _summed_objective(read)) is not None:
        merged['objective'] = objective
    return to_spec(merged)

def override(base: Source, patches: Sequence[Source]) -> Spec:
    """*base* with each patch laid over it in turn.

    Args:
        base: The spec being extended: a YAML path, YAML text, a mapping, or a
            loaded [`Spec`][mathspec.spec.Spec].
        patches: Each patch as a YAML path, YAML text, a mapping, or a loaded
            [`Spec`][mathspec.spec.Spec]. Each is laid on the base with every
            earlier patch laid on it, so a later patch wins a field an earlier
            one writes.

    Returns:
        The patched spec, loaded.

    Raises:
        LanguageError: The base does not load; the patched spec does not
            load; a patch edits or removes a declaration its base does not
            declare; a patch creates one that is not whole; a patch redeclares
            or removes a dimension or a relation; or a patch sets a whole
            section to ``null``.
        FileNotFoundError: A ``str`` with no newline that names no file.
        TypeError: *patches* is one path rather than a list.
    """
    read = {name: _declarations(patch) for name, patch in _labelled(patches, 'patches').items()}
    result = to_spec(base).to_dict()
    for name, patch in read.items():
        result = _lay_over(result, deepcopy(patch), name)
    return to_spec(result)

def to_latex(spec: str | Path | Mapping[str, object] | Spec | Program, **options: Unpack[_Options]) -> str:
    """Render *spec* as LaTeX (amsmath ``align``). See [`typeset`][]."""
    return typeset(spec, 'latex', **options)

def to_typst(spec: str | Path | Mapping[str, object] | Spec | Program, **options: Unpack[_Options]) -> str:
    """Render *spec* as Typst. See [`typeset`][]."""
    return typeset(spec, 'typst', **options)

def to_markdown(spec: str | Path | Mapping[str, object] | Spec | Program, **options: Unpack[_Options]) -> str:
    """Render *spec* as GitHub-flavoured Markdown. See [`typeset`][]."""
    return typeset(spec, 'markdown', **options)

def typeset(
    spec: str | Path | Mapping[str, object] | Spec | Program,
    fmt: FormatName,
    *,
    symbols: str | Path | Mapping[str, object] | SymbolTable | None = None,
    standalone: bool = False,
    legend: bool = True,
    numbered: bool = True,
    inline_expressions: bool = False,
) -> str:
    """Render *spec*'s math in *fmt*.

    Args:
        spec: Anything [`mathspec.to_spec`][] accepts, or a
            [`Program`][]. A ``Spec`` or a ``Program``
            is rendered as it stands, so printing one spec in several formats
            reads and checks the file once rather than once per format, and a
            curve prints as the curve it states. Pass ``spec.expand()`` for the rows a solver holds
            instead.
        fmt: What spells the math — a key of [`FORMATS`][].
        symbols: How names print, as a [`SymbolTable`][], a path or a
            mapping. Names it does not carry are derived, and it must be
            written in *fmt*'s notation.
        standalone: Emit a compilable document rather than a fragment.
        legend: Prepend the sets/parameters/variables table. The spec's own
            ``description:`` opens the document either way — it is what the
            file says it is, not a symbol table.
        numbered: Number the equations.
        inline_expressions: Substitute each plain named expression into the equations that
            use it, rather than printing its symbol there and its definition
            once. A cased expression is a definition either way: its block is
            taller than the line it would sit in.

    Returns:
        The rendered text.

    Raises:
        ValueError: *fmt* names no format.
        LanguageError: A spec that does not compile; it does not print.
        SchemaError: A symbol table entry naming nothing in the spec, or a
            table written in a notation *fmt* does not read.
    """
    walk = _walk(spec, fmt, symbols, inline_expressions=inline_expressions)
    program, format_ = walk.program, walk.format

    rendered = [
        format_.section(title, format_.equations(lines, numbered=numbered))
        for title, lines in walk.equations()
        if lines
    ]

    blocks = [format_.note(format_.escape(program.description))] if program.description else []
    if legend:
        explained, noticed = Legend(program, walk.symbols, format_), notice(program)
        blocks += [
            format_.section(title, format_.glossary(entries))
            for title, entries in explained.glossaries(noticed, walk.defined())
        ]
        blocks += [format_.note(text) for text in explained.convention_notes()]
        blocks += [format_.note(text) for text in explained.translation_notes(noticed)]
        blocks += [format_.note(text) for text in explained.position_notes(noticed)]
    return format_.document([*blocks, *rendered], standalone=standalone)

def typeset_declaration(
    spec: str | Path | Mapping[str, object] | Spec | Program,
    name: str,
    fmt: FormatName,
    *,
    symbols: str | Path | Mapping[str, object] | SymbolTable | None = None,
    inline_expressions: bool = True,
) -> str:
    """Render one declaration as the bare line the document prints for it.

    The line the whole-spec render prints for it — a named expression's
    definition, a constraint, an assumption, a ``piecewise:`` curve, or a
    variable's domain, quantifier included —
    with no document, label, equation number or math delimiters around it, for
    a math context the caller lays out: a docstring, a table cell. A line on
    its own has no Definitions section beside it, so the plain named
    expressions it uses are substituted unless *inline_expressions* says otherwise; a cased
    one prints by symbol, and a second call with its name prints its block.

    Args:
        spec: Anything [`mathspec.to_spec`][] accepts, or a [`Program`][].
        name: A named expression, constraint, assumption, ``piecewise:``
            block or variable the spec declares.
        fmt: What spells the math — a key of [`FORMATS`][].
        symbols: How names print; see [`typeset`][].
        inline_expressions: Substitute the plain named expressions the line uses, so it
            stands on its own; ``False`` prints their symbols, as the document
            does. A plain expression asked for by name prints its definition
            either way.

    Returns:
        The line, math only.

    Raises:
        ValueError: *fmt* names no format.
        LanguageError: A spec that does not compile; it does not print.
        SchemaError: *name* is declared as none of the five, as two — a
            constraint may share a variable's name — or under ``given:``, which
            prints in the legend rather than as a line; or a symbol table entry
            names nothing in the spec.
    """
    walk = _walk(spec, fmt, symbols, inline_expressions=inline_expressions)
    given = walk.program.given
    givens = {
        'parameter': given.parameters,
        'variable': given.variables,
        'expression': given.expressions,
        'constraint': given.constraints,
    }
    given_kind = next((kind for kind, group in givens.items() if name in group), None)
    if given_kind is not None:
        msg = (
            f"'{name}' is a given {given_kind}, and a given declaration prints no line of its own — "
            f"this file reads it and does not build it. It prints in the legend, under 'Given', "
            f'so call typeset() for the whole spec.'
        )
        raise SchemaError(msg)
    return walk.format.equation(walk.line(name))

def advice(spec: str | Path | Mapping[str, object] | Spec | Program) -> tuple[Advice, ...]:
    """Everything the language advises about *spec*, decided without data.

    Advice is a note, not a refusal: a file with advice still loads.

    Args:
        spec: Anything [`to_spec`][] accepts, or a [`Program`][], read as
            it arrived. A ``piecewise:`` or ``sos:`` block is read as the rows
            it states, so the answer is the one its expansion gets, with
            nothing expanded.

    Returns:
        The never-an-axis advice in declaration order, then one note per
        declaration the program reads and does not build, then the
        unboundedness advice; ``str()`` of each is its sentence.

    Raises:
        LanguageError: *spec* does not load; [`to_spec`][] says why.
        FileNotFoundError: A ``str`` with no newline that names no file.
    """
    program = spec if isinstance(spec, Program) else to_spec(spec).program
    return tuple(_never_an_axis(program) + _given(program) + unbounded_notes(program))

def did_you_mean(name: str, known: Iterable[str], *, label: str = 'Declared', listing: bool = True) -> str:
    """The repair clause for an unrecognised name: the near miss, or the set, or nothing where *listing* is off."""
    candidates = sorted(known)
    near = difflib.get_close_matches(name, candidates, n=1, cutoff=0.6)
    if near:
        return f"Did you mean '{near[0]}'?"
    return f'{label}: {", ".join(candidates) or "nothing"}.' if listing else ''