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fix: don't allow multiple default arms for match expression #12

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Merged
merged 1 commit into from
Dec 3, 2022
Merged

fix: don't allow multiple default arms for match expression #12

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8 changes: 7 additions & 1 deletion src/parser/ast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -706,6 +706,7 @@ pub enum Expression {
},
Match {
condition: Box<Self>,
default: Option<Box<DefaultMatchArm>>,
arms: Vec<MatchArm>,
},
Throw {
Expand Down Expand Up @@ -755,9 +756,14 @@ pub struct ClosureUse {
pub by_ref: bool,
}

#[derive(Debug, PartialEq, Clone)]
pub struct DefaultMatchArm {
pub body: Expression,
}

#[derive(Debug, PartialEq, Clone)]
pub struct MatchArm {
pub conditions: Option<Vec<Expression>>,
pub conditions: Vec<Expression>,
pub body: Expression,
}

Expand Down
2 changes: 2 additions & 0 deletions src/parser/error.rs
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Expand Up @@ -33,6 +33,7 @@ pub enum ParseError {
MixingBracedAndUnBracedNamespaceDeclarations(Span),
NestedNamespaceDeclarations(Span),
ForbiddenTypeUsedInProperty(String, String, Type, Span),
MatchExpressionWithMultipleDefaultArms(Span),
}

impl Display for ParseError {
Expand Down Expand Up @@ -78,6 +79,7 @@ impl Display for ParseError {
Self::NestedNamespaceDeclarations(span) => write!(f, "Parse Error: Namespace declarations cannot be mixed on line {} column {}", span.0, span.1),
Self::UnpredictableState(span) => write!(f, "Parse Error: Reached an unpredictable state on line {} column {}", span.0, span.1),
Self::ForbiddenTypeUsedInProperty(class, prop, ty, span) => write!(f, "Parse Error: Property {}::${} cannot have type `{}` on line {} column {}", class, prop, ty, span.0, span.1),
Self::MatchExpressionWithMultipleDefaultArms(span) => write!(f, "Parse Error: Match expressions may only contain one default arm on line {} column {}", span.0, span.1),
}
}
}
36 changes: 27 additions & 9 deletions src/parser/mod.rs
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Expand Up @@ -12,6 +12,7 @@ use crate::parser::error::ParseResult;
use crate::parser::internal::ident::is_reserved_ident;
use crate::parser::internal::precedence::{Associativity, Precedence};
use crate::parser::state::State;
use crate::prelude::DefaultMatchArm;

pub mod ast;
pub mod error;
Expand Down Expand Up @@ -998,19 +999,30 @@ impl Parser {
self.rparen(state)?;
self.lbrace(state)?;

let mut default = None;
let mut arms = Vec::new();
while state.current.kind != TokenKind::RightBrace {
state.skip_comments();

let conditions = if state.current.kind == TokenKind::Default {
if state.current.kind == TokenKind::Default {
if default.is_some() {
return Err(ParseError::MatchExpressionWithMultipleDefaultArms(
state.current.span,
));
}

state.next();

// match conditions can have an extra comma at the end, including `default`.
if state.current.kind == TokenKind::Comma {
state.next();
}

None
expect_token!([TokenKind::DoubleArrow], state, "`=>`");

let body = self.expression(state, Precedence::Lowest)?;

default = Some(Box::new(DefaultMatchArm { body }));
} else {
let mut conditions = Vec::new();
while state.current.kind != TokenKind::DoubleArrow {
Expand All @@ -1023,14 +1035,16 @@ impl Parser {
}
}

Some(conditions)
};

expect_token!([TokenKind::DoubleArrow], state, "`=>`");
if !conditions.is_empty() {
expect_token!([TokenKind::DoubleArrow], state, "`=>`");
} else {
break;
}

let body = self.expression(state, Precedence::Lowest)?;
let body = self.expression(state, Precedence::Lowest)?;

arms.push(MatchArm { conditions, body });
arms.push(MatchArm { conditions, body });
}

if state.current.kind == TokenKind::Comma {
state.next();
Expand All @@ -1041,7 +1055,11 @@ impl Parser {

self.rbrace(state)?;

Expression::Match { condition, arms }
Expression::Match {
condition,
default,
arms,
}
}
TokenKind::Array => {
let mut items = vec![];
Expand Down
1 change: 1 addition & 0 deletions tests/0193/ast.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
condition: Variable {
name: "a",
},
default: None,
arms: [],
},
},
Expand Down
31 changes: 15 additions & 16 deletions tests/0194/ast.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -20,24 +20,23 @@
condition: Variable {
name: "a",
},
default: None,
arms: [
MatchArm {
conditions: Some(
[
LiteralInteger {
i: 1,
},
LiteralInteger {
i: 2,
},
LiteralInteger {
i: 3,
},
LiteralInteger {
i: 4,
},
],
),
conditions: [
LiteralInteger {
i: 1,
},
LiteralInteger {
i: 2,
},
LiteralInteger {
i: 3,
},
LiteralInteger {
i: 4,
},
],
body: Null,
},
],
Expand Down
31 changes: 15 additions & 16 deletions tests/0195/ast.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -20,24 +20,23 @@
condition: Variable {
name: "a",
},
default: None,
arms: [
MatchArm {
conditions: Some(
[
LiteralInteger {
i: 1,
},
LiteralInteger {
i: 2,
},
LiteralInteger {
i: 3,
},
LiteralInteger {
i: 4,
},
],
),
conditions: [
LiteralInteger {
i: 1,
},
LiteralInteger {
i: 2,
},
LiteralInteger {
i: 3,
},
LiteralInteger {
i: 4,
},
],
body: Null,
},
],
Expand Down
31 changes: 15 additions & 16 deletions tests/0196/ast.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -20,24 +20,23 @@
condition: Variable {
name: "a",
},
default: None,
arms: [
MatchArm {
conditions: Some(
[
LiteralInteger {
i: 1,
},
LiteralInteger {
i: 2,
},
LiteralInteger {
i: 3,
},
LiteralInteger {
i: 4,
},
],
),
conditions: [
LiteralInteger {
i: 1,
},
LiteralInteger {
i: 2,
},
LiteralInteger {
i: 3,
},
LiteralInteger {
i: 4,
},
],
body: Null,
},
],
Expand Down
37 changes: 18 additions & 19 deletions tests/0197/ast.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -20,28 +20,27 @@
condition: Variable {
name: "a",
},
arms: [
MatchArm {
conditions: Some(
[
LiteralInteger {
i: 1,
},
LiteralInteger {
i: 2,
},
LiteralInteger {
i: 3,
},
LiteralInteger {
i: 4,
},
],
),
default: Some(
DefaultMatchArm {
body: Null,
},
),
arms: [
MatchArm {
conditions: None,
conditions: [
LiteralInteger {
i: 1,
},
LiteralInteger {
i: 2,
},
LiteralInteger {
i: 3,
},
LiteralInteger {
i: 4,
},
],
body: Null,
},
],
Expand Down
7 changes: 7 additions & 0 deletions tests/0210/code.php
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Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
<?php


match ($s) {
default => 43,
default => 34,
};
1 change: 1 addition & 0 deletions tests/0210/parser-error.txt
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
MatchExpressionWithMultipleDefaultArms((6, 5)) -> Parse Error: Match expressions may only contain one default arm on line 6 column 5
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