145 lines
3.8 KiB
Rust
145 lines
3.8 KiB
Rust
//! Syntax tree nodes for expressions.
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use enum_as_inner::EnumAsInner;
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use getset::Getters;
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use crate::{
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base::{
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source_file::{SourceElement, Span},
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Handler,
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},
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lexical::{
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token::{Identifier, Punctuation, Token},
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token_stream::Delimiter,
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},
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syntax::{
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error::{Error, UnexpectedSyntax},
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parser::{Parser, Reading},
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},
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};
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use super::ConnectedList;
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/// Syntax Synopsis:
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///
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/// ```ebnf
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/// Expression:
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/// Primary
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/// ```
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, EnumAsInner)]
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#[allow(missing_docs)]
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pub enum Expression {
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Primary(Primary),
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}
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impl SourceElement for Expression {
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fn span(&self) -> Span {
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match self {
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Self::Primary(primary) => primary.span(),
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}
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}
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}
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/// Syntax Synopsis:
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///
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/// ``` ebnf
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/// Primary:
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/// FunctionCall
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/// ```
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, EnumAsInner)]
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#[allow(missing_docs)]
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pub enum Primary {
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FunctionCall(FunctionCall),
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}
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impl SourceElement for Primary {
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fn span(&self) -> Span {
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match self {
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Self::FunctionCall(function_call) => function_call.span(),
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}
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}
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}
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/// Syntax Synopsis:
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///
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/// ``` ebnf
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/// FunctionCall:
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/// Identifier '(' (Expression (',' Expression)*)? ')'
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/// ;
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/// ```
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Getters)]
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pub struct FunctionCall {
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/// The identifier of the function.
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#[get = "pub"]
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identifier: Identifier,
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/// The left parenthesis of the function call.
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#[get = "pub"]
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left_parenthesis: Punctuation,
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/// The arguments of the function call.
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#[get = "pub"]
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arguments: Option<ConnectedList<Box<Expression>, Punctuation>>,
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/// The right parenthesis of the function call.
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#[get = "pub"]
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right_parenthesis: Punctuation,
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}
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impl SourceElement for FunctionCall {
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fn span(&self) -> Span {
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self.identifier
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.span()
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.join(&self.right_parenthesis.span)
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.unwrap()
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}
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}
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impl<'a> Parser<'a> {
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/// Parses an [`Expression`]
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pub fn parse_expression(&mut self, handler: &impl Handler<Error>) -> Option<Expression> {
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Some(Expression::Primary(self.parse_primary(handler)?))
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}
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/// Parses an [`Primary`]
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pub fn parse_primary(&mut self, handler: &impl Handler<Error>) -> Option<Primary> {
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match self.stop_at_significant() {
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// identifier expression
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Reading::Atomic(Token::Identifier(identifier)) => {
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// eat the identifier
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self.forward();
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// function call
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if matches!(self.stop_at_significant(), Reading::IntoDelimited(punc) if punc.punctuation == '(')
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{
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let token_tree = self.parse_enclosed_list(
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Delimiter::Parenthesis,
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',',
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|parser| parser.parse_expression(handler).map(Box::new),
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handler,
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)?;
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Some(Primary::FunctionCall(FunctionCall {
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identifier,
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left_parenthesis: token_tree.open,
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right_parenthesis: token_tree.close,
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arguments: token_tree.list,
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}))
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} else {
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// insert parser for regular identifier here
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None
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}
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}
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unexpected => {
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// make progress
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self.forward();
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handler.receive(Error::UnexpectedSyntax(UnexpectedSyntax {
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expected: crate::syntax::error::SyntaxKind::Expression,
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found: unexpected.into_token(),
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}));
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None
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}
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}
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}
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}
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