tame/tamer/src/nir.rs

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// IR that is "near" the source code.
//
// Copyright (C) 2014-2023 Ryan Specialty, LLC.
//
// This file is part of TAME.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//! An IR that is "near" the source code.
//!
//! This IR is "near" the source code written by the user,
//! performing only basic normalization tasks like desugaring.
//! It takes a verbose input language and translates it into a much more
//! concise internal representation.
//! The hope is that most desugaring will be done by templates in the future.
//!
//! NIR cannot completely normalize the source input because it does not
//! have enough information to do so---the
//! template system requires a compile-time interpreter that is beyond
//! the capabilities of NIR,
//! and so a final normalization pass must be done later on in the
//! lowering pipeline.
//!
//! This is a streaming IR,
//! meaning that the equivalent AST is not explicitly represented as a
//! tree structure in memory.
//!
//! NIR is lossy and does not retain enough information for code
//! formatting---that
//! type of operation will require a mapping between
//! XIRF and NIR,
//! where the latter is used to gather enough context for formatting
//! and the former is used as a concrete representation of what the user
//! actually typed.
//!
//! For more information on the parser,
//! see [`parse`].
//! The entry point for NIR in the lowering pipeline is exported as
//! [`XirfToNir`].
mod air;
mod interp;
mod parse;
use crate::{
diagnose::{Annotate, Diagnostic},
f::Functor,
fmt::{DisplayWrapper, TtQuote},
parse::{util::SPair, Object, Token},
span::{Span, UNKNOWN_SPAN},
sym::SymbolId,
xir::{
attr::{Attr, AttrSpan},
fmt::TtXmlAttr,
QName,
},
};
use std::{
convert::Infallible,
error::Error,
fmt::{Debug, Display},
};
pub use air::{NirToAir, NirToAirError};
pub use interp::{InterpError, InterpState as InterpolateNir};
pub use parse::{
NirParseState as XirfToNir, NirParseStateError_ as XirfToNirError,
};
/// IR that is "near" the source code.
///
/// This represents the language of TAME after it has been extracted from
/// whatever document encloses it
/// (e.g. XML).
#[derive(Debug, PartialEq, Eq)]
pub enum Nir {
Todo,
TodoAttr(SPair),
/// Begin the definition of some [`NirEntity`] and place it atop of the
/// stack.
Open(NirEntity, Span),
/// Finish definition of a [`NirEntity`] atop of the stack and pop it.
Close(NirEntity, Span),
/// Bind the given name as an identifier for the entity atop of the
/// stack.
BindIdent(SPair),
/// Reference the value of the given identifier.
///
/// Permissible identifiers and values depend on the context in which
/// this appears.
Ref(SPair),
/// Describe the [`NirEntity`] atop of the stack.
Desc(SPair),
/// A string literal.
///
/// The meaning of this string depends on context.
/// For example,
/// it may represent literate documentation or a literal in a
/// metavariable definition.
Text(SPair),
}
impl Nir {
/// Retrieve inner [`SymbolId`] that this token represents,
/// if any.
///
/// Not all NIR tokens contain associated symbols;
/// a token's [`SymbolId`] is retained only if it provides additional
/// information over the token itself.
///
/// See also [`Nir::map`] if you wish to change the symbol.
pub fn symbol(&self) -> Option<SymbolId> {
use Nir::*;
match self {
Todo => None,
TodoAttr(spair) => Some(spair.symbol()),
Open(_, _) | Close(_, _) => None,
BindIdent(spair) | Ref(spair) | Desc(spair) | Text(spair) => {
Some(spair.symbol())
}
}
}
}
impl Functor<SymbolId> for Nir {
/// Map over a token's [`SymbolId`].
///
/// This allows modifying a token's [`SymbolId`] while retaining the
/// associated [`Span`].
/// This is the desired behavior when modifying the source code the user
/// entered,
/// since diagnostic messages will reference the original source
/// location that the modification was derived from.
///
/// If a token does not contain a symbol,
/// this returns the token unchanged.
///
/// See also [`Nir::symbol`] if you only wish to retrieve the symbol
/// rather than map over it.
fn map(self, f: impl FnOnce(SymbolId) -> SymbolId) -> Self {
use Nir::*;
match self {
Todo => self,
TodoAttr(spair) => TodoAttr(spair.map(f)),
Open(_, _) | Close(_, _) => self,
BindIdent(spair) => BindIdent(spair.map(f)),
Ref(spair) => Ref(spair.map(f)),
Desc(spair) => Desc(spair.map(f)),
Text(spair) => Text(spair.map(f)),
}
}
}
/// An object upon which other [`Nir`] tokens act.
#[derive(Debug, PartialEq, Eq)]
pub enum NirEntity {
/// Package of identifiers.
Package,
/// Rate (verb) block,
/// representing a calculation with a scalar result.
Rate,
/// Summation (Σ) expression.
Sum,
/// Product (Π) expression.
Product,
// Classification.
Classify,
/// Conjunctive (∧) expression.
All,
/// Disjunctive () expression.
Any,
/// Template parameter (metavariable).
TplParam,
}
impl NirEntity {
pub fn open<S: Into<Span>>(self, span: S) -> Nir {
Nir::Open(self, span.into())
}
pub fn close<S: Into<Span>>(self, span: S) -> Nir {
Nir::Close(self, span.into())
}
}
impl Display for NirEntity {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
use NirEntity::*;
match self {
Package => write!(f, "package"),
Rate => write!(f, "rate block"),
Sum => write!(f, "sum (∑) expression"),
Product => write!(f, "product (Π) expression"),
Classify => write!(f, "classification"),
All => write!(f, "conjunctive (∧) expression"),
Any => write!(f, "disjunctive () expression"),
TplParam => write!(f, "template param (metavariable)"),
}
}
}
impl Token for Nir {
fn ir_name() -> &'static str {
"Plain NIR"
}
/// Identifying span of a token.
///
/// An _identifying span_ is a selection of one of the (potentially
/// many) spans associated with a token that is most likely to be
/// associated with the identity of that token.
fn span(&self) -> Span {
use Nir::*;
match self {
Todo => UNKNOWN_SPAN,
TodoAttr(spair) => spair.span(),
Open(_, span) => *span,
Close(_, span) => *span,
BindIdent(spair) | Ref(spair) | Desc(spair) | Text(spair) => {
spair.span()
}
}
}
}
impl Object for Nir {}
impl Display for Nir {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
use Nir::*;
match self {
Todo => write!(f, "TODO"),
TodoAttr(spair) => write!(f, "TODO Attr {spair}"),
Open(entity, _) => write!(f, "open {entity} entity"),
Close(entity, _) => write!(f, "close {entity} entity"),
BindIdent(spair) => {
write!(f, "bind identifier {}", TtQuote::wrap(spair))
}
Ref(spair) => write!(f, "ref {}", TtQuote::wrap(spair)),
// TODO: TtQuote doesn't yet escape quotes at the time of writing!
Desc(spair) => write!(f, "description {}", TtQuote::wrap(spair)),
// TODO: Not yet safe to output arbitrary text;
// need to determine how to handle newlines and other types of
// output.
Text(_) => write!(f, "text"),
}
}
}
impl<E> From<Nir> for Result<Nir, E> {
fn from(val: Nir) -> Self {
Ok(val)
}
}
/// Tag representing the type of a NIR value.
///
/// NIR values originate from attributes,
/// which are refined into types as enough information becomes available.
/// Value parsing must be deferred if a value requires desugaring or
/// metavalue expansion.
#[derive(Debug, PartialEq, Eq)]
#[repr(u8)]
pub enum NirSymbolTy {
AnyIdent,
BooleanLiteral,
ClassIdent,
ClassIdentList,
ConstIdent,
DescLiteral,
Dim,
DynNodeLiteral,
FuncIdent,
IdentDtype,
IdentType,
MapTransformLiteral,
NumLiteral,
ParamDefault,
ParamIdent,
ParamName,
ParamType,
PkgPath,
ShortDimNumLiteral,
StringLiteral,
SymbolTableKey,
TexMathLiteral,
Title,
TplMetaIdent,
TplIdent,
TplParamIdent,
TypeIdent,
ValueIdent,
}
impl Display for NirSymbolTy {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
use NirSymbolTy::*;
match self {
AnyIdent => write!(f, "any identifier"),
BooleanLiteral => write!(
f,
"boolean literal {fmt_true} or {fmt_false}",
fmt_true = TtQuote::wrap("true"),
fmt_false = TtQuote::wrap("false"),
),
ClassIdent => write!(f, "classification identifier"),
ClassIdentList => {
write!(f, "space-delimited list of classification identifiers")
}
ConstIdent => write!(f, "constant identifier"),
DescLiteral => write!(f, "description literal"),
Dim => write!(f, "dimension declaration"),
DynNodeLiteral => write!(f, "dynamic node literal"),
FuncIdent => write!(f, "function identifier"),
IdentDtype => write!(f, "identifier primitive datatype"),
IdentType => write!(f, "identifier type"),
MapTransformLiteral => write!(f, "map transformation literal"),
NumLiteral => write!(f, "numeric literal"),
ParamDefault => write!(f, "param default"),
ParamIdent => write!(f, "param identifier"),
ParamName => write!(f, "param name"),
ParamType => write!(f, "param type"),
PkgPath => write!(f, "package path"),
ShortDimNumLiteral => {
write!(f, "short-hand dimensionalized numeric literal")
}
StringLiteral => write!(f, "string literal"),
SymbolTableKey => write!(f, "symbol table key name"),
TexMathLiteral => write!(f, "TeX math literal"),
Title => write!(f, "title"),
TplMetaIdent => write!(f, "template metadata identifier"),
TplIdent => write!(f, "template name"),
TplParamIdent => write!(f, "template param identifier"),
TypeIdent => write!(f, "type identifier"),
ValueIdent => write!(f, "value identifier"),
}
}
}
/// A ([`SymbolId`], [`Span`]) pair representing an
/// attribute value that may need to be interpreted within the context of
/// a template application.
///
/// _This object must be kept small_,
/// since it is used in objects that aggregate portions of the token
/// stream,
/// which must persist in memory for a short period of time,
/// and therefore cannot be optimized away as other portions of the IR.
#[derive(Debug, PartialEq, Eq)]
pub struct NirSymbol<const TY: NirSymbolTy>(SymbolId, Span);
impl<const TY: NirSymbolTy> Token for NirSymbol<TY> {
fn ir_name() -> &'static str {
// TODO: Include type?
"NIR Symbol"
}
fn span(&self) -> Span {
match self {
Self(_, span) => *span,
}
}
}
impl<const TY: NirSymbolTy> Display for NirSymbol<TY> {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
Self(sym, _span) => {
write!(f, "{TY} {fmt_sym}", fmt_sym = TtQuote::wrap(sym),)
}
}
}
}
impl<const TY: NirSymbolTy> From<(SymbolId, Span)> for NirSymbol<TY> {
fn from((val, span): (SymbolId, Span)) -> Self {
Self(val, span)
}
}
impl<const TY: NirSymbolTy> From<Attr> for NirSymbol<TY> {
fn from(attr: Attr) -> Self {
match attr {
Attr(_, val, AttrSpan(_, vspan)) => (val, vspan).into(),
}
}
}
// Force developer to be conscious of any changes in size;
// see `NirSymbol` docs for more information.
assert_eq_size!(NirSymbol<{ NirSymbolTy::AnyIdent }>, (SymbolId, Span));
#[derive(Debug, PartialEq, Eq)]
pub enum PkgType {
/// Package is intended to produce an executable program.
///
/// This is specified by the `rater` root node.
Prog,
/// Package is intended to be imported as a component of a larger
/// program.
Mod,
}
#[derive(Debug, PartialEq, Eq)]
pub struct Literal<const S: SymbolId>;
impl<const S: SymbolId> TryFrom<Attr> for Literal<S> {
type Error = NirAttrParseError;
fn try_from(attr: Attr) -> Result<Self, Self::Error> {
match attr {
Attr(_, val, _) if val == S => Ok(Literal),
Attr(name, _, aspan) => Err(NirAttrParseError::LiteralMismatch(
name,
aspan.value_span(),
S,
)),
}
}
}
impl From<Infallible> for NirAttrParseError {
fn from(x: Infallible) -> Self {
match x {}
}
}
type ExpectedSymbolId = SymbolId;
#[derive(Debug, PartialEq, Eq)]
pub enum NirAttrParseError {
LiteralMismatch(QName, Span, ExpectedSymbolId),
}
impl Error for NirAttrParseError {
fn source(&self) -> Option<&(dyn Error + 'static)> {
None
}
}
impl Display for NirAttrParseError {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
Self::LiteralMismatch(name, _, _) => {
write!(f, "unexpected value for {}", TtXmlAttr::wrap(name),)
}
}
}
}
impl Diagnostic for NirAttrParseError {
fn describe(&self) -> Vec<crate::diagnose::AnnotatedSpan> {
match self {
Self::LiteralMismatch(_, span, expected) => span
.error(format!("expecting {}", TtQuote::wrap(expected)))
.into(),
}
}
}