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parser_test.go
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parser_test.go
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package main
import (
"encoding/json"
"fmt"
"testing"
"github.com/mbivert/ftests"
)
// unexported fields are unavailable to the json
// package, and thus aren't visible in tests...
func (e *IntExpr) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
D string
T Type
V int64
}{
D: "int",
T: e.getType(),
V: e.v,
})
}
func (e *FloatExpr) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
D string
T Type
V float64
}{
D: "float",
T: e.getType(),
V: e.v,
})
}
func (e *BoolExpr) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
D string
T Type
V bool
}{
D: "bool",
T: e.getType(),
V: e.v,
})
}
func (e *AbsExpr) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
D string
T Type
Typ Type
Name string
Right Expr
}{
D: "abs",
T: e.getType(),
Typ: e.typ,
Name: e.name,
Right: e.right,
})
}
func (e *AppExpr) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
D string
T Type
Left Expr
Right Expr
}{
D: "app",
T: e.getType(),
Left: e.left,
Right: e.right,
})
}
func (e *VarExpr) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
D string
T Type
Name string
}{
D: "var",
T: e.getType(),
Name: e.name,
})
}
func (e *BinaryExpr) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
D string
T Type
Op string
Left Expr
Right Expr
}{
D: "bin",
T: e.getType(),
Op: e.op.String(),
Left: e.left,
Right: e.right,
})
}
func (e *UnaryExpr) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
D string
T Type
Op string
Right Expr
}{
D: "una",
T: e.getType(),
Op: e.op.String(),
Right: e.right,
})
}
// unexported fields are unavailable to the json
// package, and thus aren't visible in tests...
func (t *IntType) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
T string
}{
T: "int",
})
}
func (t *FloatType) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
T string
}{
T: "float",
})
}
func (t *BoolType) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
T string
}{
T: "bool",
})
}
func (t *UnitType) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
T string
}{
T: "unit",
})
}
func (t *ArrowType) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
T string
Left Type
Right Type
}{
T: "arrow",
Left: t.left,
Right: t.right,
})
}
func (t *ProductType) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
T string
Left Type
Right Type
}{
T: "product",
Left: t.left,
Right: t.right,
})
}
func (t *VarType) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
T string
Name string
}{
T: "var",
Name: t.name,
})
}
/*
* Many of those tests are recycled from
* https://github.com/mbivert/nix-series-code/blob/master/lambda/parse_test.nix
* https://github.com/mbivert/nix-series-code/blob/master/exprs_test.nix
*
* More tests to import from:
* https://github.com/mbivert/nix-series-code/blob/master/lambda_test.nix
*
* We're focusing here on basic lambda calculus extended with some
* scalar types (eg. bool, int, float) and basic arithmetic operations.
*/
func TestParserMathExprs(t *testing.T) {
ftests.Run(t, []ftests.Test{
{
"empty input",
parse,
[]any{"", ""},
[]any{nil, fmt.Errorf(":1:1: Unexpected token: EOF")},
},
{
"single int",
parse,
[]any{" 1234", ""},
[]any{&IntExpr{expr{&IntType{}}, 1234}, nil},
},
{
"single (int)",
parse,
[]any{" (1234)", ""},
[]any{&IntExpr{expr{&IntType{}}, 1234}, nil},
},
{
"single ((int))",
parse,
[]any{" ((1234))", ""},
[]any{&IntExpr{expr{&IntType{}}, 1234}, nil},
},
{
"single float",
parse,
[]any{" 1234.45 ", ""},
[]any{&FloatExpr{expr{&FloatType{}}, 1234.45}, nil},
},
{
"single boolean",
parse,
[]any{" true ", ""},
[]any{&BoolExpr{expr{&BoolType{}}, true}, nil},
},
{
"single boolean (bis)",
parse,
[]any{" false ", ""},
[]any{&BoolExpr{expr{&BoolType{}}, false}, nil},
},
// NOTE: this will be rejected during the type inference/checking phase
{
"two consecutives ints: 'bad' function call, still parses OK",
parse,
[]any{" 1234 12", ""},
[]any{
&AppExpr{expr{}, &IntExpr{expr{&IntType{}}, 1234}, &IntExpr{expr{&IntType{}}, 12}},
nil,
},
},
{
"unary expression: -12",
parse,
[]any{" - 12", ""},
[]any{
&UnaryExpr{expr{}, tokenMinus, &IntExpr{expr{&IntType{}}, 12}},
nil,
},
},
{
"unary expression: +.12",
parse,
[]any{" +. 12", ""},
[]any{
&UnaryExpr{expr{}, tokenFPlus, &IntExpr{expr{&IntType{}}, 12}},
nil,
},
},
{
"unary expressions: ++.12",
parse,
[]any{" ++. 12", ""},
[]any{
&UnaryExpr{
expr{},
tokenPlus,
&UnaryExpr{expr{}, tokenFPlus, &IntExpr{expr{&IntType{}}, 12}},
},
nil,
},
},
{
"single float in parentheses",
parse,
[]any{" (1234.45) ", ""},
[]any{&FloatExpr{expr{&FloatType{}}, 1234.45}, nil},
},
{
"single float in two pairs of parentheses",
parse,
[]any{" ( (1234.45)\t) ", ""},
[]any{&FloatExpr{expr{&FloatType{}}, 1234.45}, nil},
},
{
"Missing parenthesis",
parse,
[]any{" ( (1234.45)\t ", ""},
[]any{
nil,
fmt.Errorf(":1:17: Expecting left paren, got: EOF"),
},
},
{
"single float in two pairs of parentheses, many unary operators",
parse,
[]any{" +.( - (-.-1234.45)\t) ", ""},
[]any{
&UnaryExpr{
expr{},
tokenFPlus,
&UnaryExpr{
expr{},
tokenMinus,
&UnaryExpr{
expr{},
tokenFMinus,
&UnaryExpr{
expr{},
tokenMinus,
&FloatExpr{expr{&FloatType{}}, 1234.45},
},
},
},
},
nil,
},
},
{
"left-associativy, addition",
parse,
[]any{"1+2+ 3 ", ""},
[]any{
&BinaryExpr{
expr{},
tokenPlus,
&BinaryExpr{
expr{},
tokenPlus,
&IntExpr{expr{&IntType{}}, 1},
&IntExpr{expr{&IntType{}}, 2},
},
&IntExpr{expr{&IntType{}}, 3},
},
nil,
},
},
{
"left-associativy, addition/substraction: 1-42+12 ≠ 1-(42+12)",
parse,
[]any{"1-42+12", ""},
[]any{
&BinaryExpr{
expr{},
tokenPlus,
&BinaryExpr{
expr{},
tokenMinus,
&IntExpr{expr{&IntType{}}, 1},
&IntExpr{expr{&IntType{}}, 42},
},
&IntExpr{expr{&IntType{}}, 12},
},
nil,
},
},
{
"multiplication has precedence over addition",
parse,
[]any{"1.*.2.+. 3. ", ""},
[]any{
&BinaryExpr{
expr{},
tokenFPlus,
&BinaryExpr{
expr{},
tokenFStar,
&FloatExpr{expr{&FloatType{}}, 1.},
&FloatExpr{expr{&FloatType{}}, 2.},
},
&FloatExpr{expr{&FloatType{}}, 3.},
},
nil,
},
},
{
"random expression",
parse,
[]any{"1.*.(2.+. 3.)", ""},
[]any{
&BinaryExpr{
expr{},
tokenFStar,
&FloatExpr{expr{&FloatType{}}, 1.},
&BinaryExpr{
expr{},
tokenFPlus,
&FloatExpr{expr{&FloatType{}}, 2.},
&FloatExpr{expr{&FloatType{}}, 3.},
},
},
nil,
},
},
{
"Comparison: x < 3",
parse,
[]any{"x < 3", ""},
[]any{
&BinaryExpr{
expr{},
tokenLess,
&VarExpr{expr{}, "x"},
&IntExpr{expr{&IntType{}}, 3},
},
nil,
},
},
{
"Comparison: x < (3+67)",
parse,
[]any{"x < (3 +67)", ""},
[]any{
&BinaryExpr{
expr{},
tokenLess,
&VarExpr{expr{}, "x"},
&BinaryExpr{
expr{},
tokenPlus,
&IntExpr{expr{&IntType{}}, 3},
&IntExpr{expr{&IntType{}}, 67},
},
},
nil,
},
},
{
"1- 3 * 5 + (1 + 34 )/ 3.",
parse,
[]any{"1- 3 * 5 + (1 + 34 )/ 3.", ""},
[]any{
&BinaryExpr{
expr{},
tokenPlus,
&BinaryExpr{
expr{},
tokenMinus,
&IntExpr{expr{&IntType{}}, 1},
&BinaryExpr{
expr{},
tokenStar,
&IntExpr{expr{&IntType{}}, 3},
&IntExpr{expr{&IntType{}}, 5},
},
},
&BinaryExpr{
expr{},
tokenSlash,
&BinaryExpr{
expr{},
tokenPlus,
&IntExpr{expr{&IntType{}}, 1},
&IntExpr{expr{&IntType{}}, 34},
},
&FloatExpr{expr{&FloatType{}}, 3.},
},
},
nil,
},
},
{
"0 / 78 * 12",
parse,
[]any{"0 / 78 * 12", ""},
[]any{
&BinaryExpr{
expr{},
tokenStar,
&BinaryExpr{
expr{},
tokenSlash,
&IntExpr{expr{&IntType{}}, 0},
&IntExpr{expr{&IntType{}}, 78},
},
&IntExpr{expr{&IntType{}}, 12},
},
nil,
},
},
{
"!(true)",
parse,
[]any{"!(true)", ""},
[]any{
&UnaryExpr{
expr{},
tokenExcl,
&BoolExpr{expr{&BoolType{typ{}}}, true},
},
nil,
},
},
{
"3. ≤. 5.",
parse,
[]any{"3. ≤. 5.", ""},
[]any{
&BinaryExpr{
expr{},
tokenFLessEq,
&FloatExpr{expr{&FloatType{}}, 3.},
&FloatExpr{expr{&FloatType{}}, 5.},
},
nil,
},
},
})
}
func TestParserUntypedλCalc(t *testing.T) {
ftests.Run(t, []ftests.Test{
{
"basic abstraction",
parse,
[]any{"λx.x", ""},
[]any{
&AbsExpr{
expr{},
&typ{},
"x",
&VarExpr{expr{}, "x"},
},
nil,
},
},
{
"basic abstraction (optional λ)",
parse,
[]any{"x.x", ""},
[]any{
&AbsExpr{
expr{},
&typ{},
"x",
&VarExpr{expr{}, "x"},
},
nil,
},
},
{
"abstraction: syntax error (missing dot)",
parse,
[]any{"\nλx x", ""},
[]any{
nil,
fmt.Errorf(":2:4: Expecting dot after lambda variable name, got: name"),
},
},
{
"abstraction: syntax error (missing variable name)",
parse,
[]any{"\nλ.x x", ""},
[]any{
nil,
fmt.Errorf(":2:2: Expecting variable name after lambda, got: ."),
},
},
{
"abstraction: syntax error (missing variable name)",
parse,
[]any{"λx. ", ""},
[]any{
nil,
fmt.Errorf(":1:5: Unexpected token: EOF"),
},
},
{
"(λx. x x) (λx. x x)",
parse,
[]any{"(λx. x x) (λx. x x)", ""},
[]any{
&AppExpr{
expr{},
&AbsExpr{
expr{},
&typ{},
"x",
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "x"},
},
},
&AbsExpr{
expr{},
&typ{},
"x",
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "x"},
},
},
},
nil,
},
},
{
"(λx. (λy. x))",
parse,
[]any{"(λx. (λy. x))", ""},
[]any{T, nil},
},
{
"(λx. λy. x)",
parse,
[]any{"(λx. λy. x)", ""},
[]any{T, nil},
},
{
"λx.λy.x",
parse,
[]any{"λx.λy.x", ""},
[]any{T, nil},
},
{
"x. (one (two (three (four five))))",
parse,
[]any{"x. (one (two (three (four five))))", ""},
[]any{
&AbsExpr{
expr{},
&typ{},
"x",
&AppExpr{
expr{},
&VarExpr{expr{}, "one"},
&AppExpr{
expr{},
&VarExpr{expr{}, "two"},
&AppExpr{
expr{},
&VarExpr{expr{}, "three"},
&AppExpr{
expr{},
&VarExpr{expr{}, "four"},
&VarExpr{expr{}, "five"},
},
},
},
},
},
nil,
},
},
{
"x. one two three four five",
parse,
[]any{"x. one two three four five", ""},
[]any{
&AbsExpr{
expr{},
&typ{},
"x",
&AppExpr{
expr{},
&AppExpr{
expr{},
&AppExpr{
expr{},
&AppExpr{
expr{},
&VarExpr{expr{}, "one"},
&VarExpr{expr{}, "two"},
},
&VarExpr{expr{}, "three"},
},
&VarExpr{expr{}, "four"},
},
&VarExpr{expr{}, "five"},
},
},
nil,
},
},
})
}
func TestParserPrimitiveType(t *testing.T) {
ftests.Run(t, []ftests.Test{
{
"boolean",
parse,
[]any{"λx : bool . x && y", ""},
[]any{
&AbsExpr{
expr{},
&BoolType{},
"x",
&BinaryExpr{
expr{},
tokenAndAnd,
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
},
nil,
},
},
{
"int",
parse,
[]any{"λx : int . x + y", ""},
[]any{
&AbsExpr{
expr{},
&IntType{},
"x",
&BinaryExpr{
expr{},
tokenPlus,
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
},
nil,
},
},
{
"float",
parse,
[]any{"λx : float . x +. y", ""},
[]any{
&AbsExpr{
expr{},
&FloatType{},
"x",
&BinaryExpr{
expr{},
tokenFPlus,
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
},
nil,
},
},
{
"float",
parse,
[]any{"λx : unit. *", ""},
[]any{
&AbsExpr{
expr{},
&UnitType{},
"x",
&UnitExpr{expr{&UnitType{}}},
},
nil,
},
},
})
}
func TestParserArrowType(t *testing.T) {
ftests.Run(t, []ftests.Test{
{
"bool → bool",
parse,
[]any{"λx : bool → bool . x y", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{typ{}, &BoolType{}, &BoolType{}},
"x",
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
},
nil,
},
},
{
"bool → bool → bool (right associative: bool → (bool → bool))",
parse,
[]any{"λx : bool → bool → bool . x y z", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{
typ{}, &BoolType{}, &ArrowType{
typ{}, &BoolType{}, &BoolType{},
},
},
"x",
&AppExpr{
expr{},
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
&VarExpr{expr{}, "z"},
},
},
nil,
},
},
{
"bool → bool → bool → int",
parse,
[]any{"λx : bool → bool → bool → int . (x y z) + 3", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{
typ{}, &BoolType{}, &ArrowType{
typ{}, &BoolType{}, &ArrowType{
typ{}, &BoolType{}, &IntType{},
},
},
},
"x",
&BinaryExpr{
expr{},
tokenPlus,
&AppExpr{
expr{},
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
&VarExpr{expr{}, "z"},
},
&IntExpr{expr{&IntType{}}, 3},
},
},
nil,
},
},
{
"(bool → bool) → bool (manually altered associativity)",
parse,
[]any{"λx : (bool → bool) → bool . x y z", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{
typ{}, &ArrowType{
typ{}, &BoolType{}, &BoolType{},
},
&BoolType{},
},
"x",
&AppExpr{
expr{},
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
&VarExpr{expr{}, "z"},
},
},
nil,
},
},
})
}
// same as TestArrowType(), but systematically using the short
// form (x: $type . $expr instead of λx: $type . $expr
func TestParserArrowTypeShort(t *testing.T) {
ftests.Run(t, []ftests.Test{
{
"bool → bool",
parse,
[]any{"x : bool → bool . x y", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{typ{}, &BoolType{}, &BoolType{}},
"x",
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
},
nil,
},
},
{
"bool → bool → bool (right associative: bool → (bool → bool))",
parse,
[]any{"x : bool → bool → bool . x y z", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{
typ{}, &BoolType{}, &ArrowType{
typ{}, &BoolType{}, &BoolType{},
},
},
"x",
&AppExpr{
expr{},
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
&VarExpr{expr{}, "z"},
},
},
nil,
},
},
{
"bool → bool → bool → int",
parse,
[]any{"x : bool → bool → bool → int . (x y z) + 3", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{
typ{}, &BoolType{}, &ArrowType{
typ{}, &BoolType{}, &ArrowType{
typ{}, &BoolType{}, &IntType{},
},
},
},
"x",
&BinaryExpr{
expr{},
tokenPlus,
&AppExpr{
expr{},
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
&VarExpr{expr{}, "z"},
},
&IntExpr{expr{&IntType{}}, 3},
},
},
nil,
},
},
{
"(bool → bool) → bool (manually altered associativity)",
parse,
[]any{"x : (bool → bool) → bool . x y z", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{
typ{}, &ArrowType{
typ{}, &BoolType{}, &BoolType{},
},
&BoolType{},
},
"x",
&AppExpr{
expr{},
&AppExpr{
expr{},
&VarExpr{expr{}, "x"},
&VarExpr{expr{}, "y"},
},
&VarExpr{expr{}, "z"},
},
},
nil,
},
},
})
}
// "we adopt the convention that × binds stronger than →"
func TestParserArrowProductType(t *testing.T) {
ftests.Run(t, []ftests.Test{
{
"bool × int → bool := (bool×int) → bool",
parse,
[]any{"λx : bool×int → bool . x y", ""},
[]any{
&AbsExpr{
expr{},
&ArrowType{typ{}, &ProductType{
typ{}, &BoolType{}, &IntType{},