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Merged
antonmedv merged 3 commits into from
Dec 14, 2025
+102 −35
Merged

Add else if support #879

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b02b0cf
Add `else if` support
antonmedv Dec 14, 2025
5052a11
Add test for nested `else if` handling
antonmedv Dec 14, 2025
ce727bc
Add `Ternary` field to `ConditionalNode` and update tests and printin…
antonmedv Dec 14, 2025
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9 changes: 5 additions & 4 deletions ast/node.go
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Original file line number Diff line number Diff line change
Expand Up @@ -200,12 +200,13 @@ type PointerNode struct {
Name string // Name of the pointer. Like "index" in "#index".
}

// ConditionalNode represents a ternary operator.
// ConditionalNode represents a ternary operator or if/else operator.
type ConditionalNode struct {
base
Cond Node // Condition of the ternary operator. Like "foo" in "foo ? bar : baz".
Exp1 Node // Expression 1 of the ternary operator. Like "bar" in "foo ? bar : baz".
Exp2 Node // Expression 2 of the ternary operator. Like "baz" in "foo ? bar : baz".
Ternary bool // Is it ternary or if/else operator?
Cond Node // Condition
Exp1 Node // Expression 1
Exp2 Node // Expression 2
}

// VariableDeclaratorNode represents a variable declaration.
Expand Down
10 changes: 10 additions & 0 deletions ast/print.go
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Expand Up @@ -207,6 +207,16 @@ func (n *SequenceNode) String() string {
}

func (n *ConditionalNode) String() string {
if !n.Ternary {
cond := n.Cond.String()
exp1 := n.Exp1.String()
if c2, ok := n.Exp2.(*ConditionalNode); ok && !c2.Ternary {
return fmt.Sprintf("if %s { %s } else %s", cond, exp1, c2.String())
}
exp2 := n.Exp2.String()
return fmt.Sprintf("if %s { %s } else { %s }", cond, exp1, exp2)
}

var cond, exp1, exp2 string
if _, ok := n.Cond.(*ConditionalNode); ok {
cond = fmt.Sprintf("(%s)", n.Cond.String())
Expand Down
3 changes: 2 additions & 1 deletion ast/print_test.go
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Expand Up @@ -83,7 +83,8 @@ func TestPrint(t *testing.T) {
{`(2 ** 2) ** 3`, `(2 ** 2) ** 3`},
{`(3 + 5) / (5 % 3)`, `(3 + 5) / (5 % 3)`},
{`(-(1+1)) == 2`, `-(1 + 1) == 2`},
{`if true { 1 } else { 2 }`, `true ? 1 : 2`},
{`if true { 1 } else { 2 }`, `if true { 1 } else { 2 }`},
{`if true { 1 } else if false { 2 } else { 3 }`, `if true { 1 } else if false { 2 } else { 3 }`},
}

for _, tt := range tests {
Expand Down
4 changes: 4 additions & 0 deletions expr_test.go
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Expand Up @@ -1390,6 +1390,10 @@ func TestExpr(t *testing.T) {
`if "a" < "b" {let x = "a"; x} else {"abc"}`,
"a",
},
{
`if 1 == 2 { "no" } else if 1 == 1 { "yes" } else { "maybe" }`,
"yes",
},
Comment on lines +1393 to +1396
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Copilot AI Dec 14, 2025

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Consider adding a test case with multiple chained else if statements to ensure the feature works correctly for longer chains. For example: if 1 == 2 { "a" } else if 2 == 3 { "b" } else if 3 == 3 { "c" } else { "d" } with expected result "c".

Copilot uses AI. Check for mistakes.
{
`1; 2; 3`,
3,
Expand Down
19 changes: 13 additions & 6 deletions parser/parser.go
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Original file line number Diff line number Diff line change
Expand Up @@ -334,9 +334,15 @@ func (p *Parser) parseConditionalIf() Node {
expr1 := p.parseSequenceExpression()
p.expect(Bracket, "}")
p.expect(Operator, "else")
p.expect(Bracket, "{")
expr2 := p.parseSequenceExpression()
p.expect(Bracket, "}")

var expr2 Node
if p.current.Is(Operator, "if") {
expr2 = p.parseConditionalIf()
} else {
p.expect(Bracket, "{")
expr2 = p.parseSequenceExpression()
p.expect(Bracket, "}")
}

return &ConditionalNode{
Cond: nodeCondition,
Expand All @@ -362,9 +368,10 @@ func (p *Parser) parseConditional(node Node) Node {
}

node = p.createNode(&ConditionalNode{
Cond: node,
Exp1: expr1,
Exp2: expr2,
Ternary: true,
Cond: node,
Exp1: expr1,
Exp2: expr2,
}, p.current.Location)
if node == nil {
return nil
Expand Down
92 changes: 68 additions & 24 deletions parser/parser_test.go
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Expand Up @@ -197,15 +197,19 @@ world`},
},
{
"true ? true : false",
&ConditionalNode{Cond: &BoolNode{Value: true},
Exp1: &BoolNode{Value: true},
Exp2: &BoolNode{}},
&ConditionalNode{
Ternary: true,
Cond: &BoolNode{Value: true},
Exp1: &BoolNode{Value: true},
Exp2: &BoolNode{}},
},
{
"a?[b]:c",
&ConditionalNode{Cond: &IdentifierNode{Value: "a"},
Exp1: &ArrayNode{Nodes: []Node{&IdentifierNode{Value: "b"}}},
Exp2: &IdentifierNode{Value: "c"}},
&ConditionalNode{
Ternary: true,
Cond: &IdentifierNode{Value: "a"},
Exp1: &ArrayNode{Nodes: []Node{&IdentifierNode{Value: "b"}}},
Exp2: &IdentifierNode{Value: "c"}},
},
{
"a.b().c().d[33]",
Expand Down Expand Up @@ -396,6 +400,7 @@ world`},
{
"2==2 ? false : 3 not in [1, 2, 5]",
&ConditionalNode{
Ternary: true,
Cond: &BinaryNode{
Operator: "==",
Left: &IntegerNode{Value: 2},
Expand Down Expand Up @@ -659,6 +664,29 @@ world`},
Exp1: &BoolNode{Value: true},
Exp2: &IdentifierNode{Value: "x"}},
},
{
"if a { 1 } else if b { 2 } else { 3 }",
&ConditionalNode{
Cond: &IdentifierNode{Value: "a"},
Exp1: &IntegerNode{Value: 1},
Exp2: &ConditionalNode{
Cond: &IdentifierNode{Value: "b"},
Exp1: &IntegerNode{Value: 2},
Exp2: &IntegerNode{Value: 3}}},
},
Comment on lines +667 to +676
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Copilot AI Dec 14, 2025

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Consider adding a test case for multiple chained else if statements to verify that the recursive implementation correctly handles chains longer than two conditionals. For example: if a { 1 } else if b { 2 } else if c { 3 } else { 4 } would test that the parser can handle arbitrarily long chains of conditionals.

Copilot uses AI. Check for mistakes.
{
"if a { 1 } else if b { 2 } else if c { 3 } else { 4 }",
&ConditionalNode{
Cond: &IdentifierNode{Value: "a"},
Exp1: &IntegerNode{Value: 1},
Exp2: &ConditionalNode{
Cond: &IdentifierNode{Value: "b"},
Exp1: &IntegerNode{Value: 2},
Exp2: &ConditionalNode{
Cond: &IdentifierNode{Value: "c"},
Exp1: &IntegerNode{Value: 3},
Exp2: &IntegerNode{Value: 4}}}},
},
{
"1; 2; 3",
&SequenceNode{
Expand Down Expand Up @@ -687,9 +715,10 @@ world`},
&SequenceNode{
Nodes: []Node{
&ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &IntegerNode{Value: 2}},
Ternary: true,
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &IntegerNode{Value: 2}},
&IntegerNode{Value: 3},
&IntegerNode{Value: 4},
},
Expand All @@ -698,8 +727,9 @@ world`},
{
"true ? 1 : ( 2; 3; 4 )",
&ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Ternary: true,
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &SequenceNode{
Nodes: []Node{
&IntegerNode{Value: 2},
Expand All @@ -714,9 +744,10 @@ world`},
&SequenceNode{
Nodes: []Node{
&ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &BoolNode{Value: true},
Exp2: &IntegerNode{Value: 1}},
Ternary: true,
Cond: &BoolNode{Value: true},
Exp1: &BoolNode{Value: true},
Exp2: &IntegerNode{Value: 1}},
&IntegerNode{Value: 2},
&IntegerNode{Value: 3},
},
Expand All @@ -727,18 +758,20 @@ world`},
&VariableDeclaratorNode{
Name: "x",
Value: &ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &IntegerNode{Value: 2}},
Ternary: true,
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &IntegerNode{Value: 2}},
Expr: &IdentifierNode{Value: "x"}},
},
{
"let x = true ? 1 : ( 2; 3; 4 ); x",
&VariableDeclaratorNode{
Name: "x",
Value: &ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Ternary: true,
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &SequenceNode{
Nodes: []Node{
&IntegerNode{Value: 2},
Expand All @@ -762,7 +795,8 @@ world`},
Nodes: []Node{
&IntegerNode{Value: 4},
&IntegerNode{Value: 5},
&IntegerNode{Value: 6}}}},
&IntegerNode{Value: 6}}},
},
},
{
`all(ls, if true { 1 } else { 2 })`,
Expand All @@ -774,7 +808,8 @@ world`},
Node: &ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &IntegerNode{Value: 2}}}}},
Exp2: &IntegerNode{Value: 2},
}}}},
},
{
`let x = if true { 1 } else { 2 }; x`,
Expand All @@ -783,7 +818,8 @@ world`},
Value: &ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &IntegerNode{Value: 2}},
Exp2: &IntegerNode{Value: 2},
},
Expr: &IdentifierNode{Value: "x"}},
},
{
Expand All @@ -794,7 +830,8 @@ world`},
&ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &IntegerNode{Value: 2}}}},
Exp2: &IntegerNode{Value: 2},
}}},
},
{
`[if true { 1 } else { 2 }]`,
Expand All @@ -803,7 +840,8 @@ world`},
&ConditionalNode{
Cond: &BoolNode{Value: true},
Exp1: &IntegerNode{Value: 1},
Exp2: &IntegerNode{Value: 2}}}},
Exp2: &IntegerNode{Value: 2},
}}},
},
{
`map(ls, { 1; 2; 3 })`,
Expand Down Expand Up @@ -1019,6 +1057,12 @@ func TestParse_error(t *testing.T) {
`unexpected token Operator("if") (1:5)
| 1 + if true { 2 } else { 3 }
| ....^`,
},
{
`if a { 1 } else b`,
`unexpected token Identifier("b") (1:17)
| if a { 1 } else b
| ................^`,
},
{
`list | all(#,,)`,
Expand Down
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