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|
package moonbitlang_test
import (
"strings"
"testing"
"rickub.com/turbo-editors/turbo-core/syntax"
"rickub.com/turbo-editors/turbo-moonbit/internal/moonbitlang"
)
// coloured is one span with the text it covers, which is what a test wants to
// talk about: "the word fn is a keyword", not "columns 0 to 2 are class 1".
type coloured struct {
text string
class syntax.Class
}
func (c coloured) String() string { return c.text + ":" + c.class.String() }
// colouredLine returns every span of one line of source, with its text.
func colouredLine(t *testing.T, src string) []coloured {
t.Helper()
lines := moonbitlang.Highlight(src)
if len(lines) != 1 {
t.Fatalf("Highlight(%q) returned %d lines, want 1", src, len(lines))
}
return withText([]rune(src), lines[0])
}
// withText pairs each span with the runes it covers.
func withText(line []rune, spans []syntax.Span) []coloured {
out := make([]coloured, 0, len(spans))
for _, span := range spans {
out = append(out, coloured{string(line[span.Start:span.End]), span.Class})
}
return out
}
// find returns the span covering exactly the given text, if there is one.
func find(spans []coloured, text string) (coloured, bool) {
for _, span := range spans {
if span.text == text {
return span, true
}
}
return coloured{}, false
}
// assertClass fails unless one span covers exactly text and has the wanted
// class. Asking for the whole text means a scanner that split a construct in
// two is caught, not only one that coloured it wrongly.
func assertClass(t *testing.T, src, text string, want syntax.Class) {
t.Helper()
spans := colouredLine(t, src)
got, ok := find(spans, text)
if !ok {
t.Fatalf("in %q: no single span covers %q; got %v", src, text, spans)
}
if got.class != want {
t.Errorf("in %q: %q is %s, want %s", src, text, got.class, want)
}
}
// --- the three invariants the editor relies on ------------------------------
// A representative body of MoonBit, used by the invariant tests below. It is
// deliberately a mixture: every construct the scanner knows, some broken input,
// and the constructs that most easily run into one another.
const sample = `///| A doc comment.
// An ordinary one.
#deprecated("use area instead")
pub fn area(shape : Shape, scale~ : Double = 1.0) -> Double raise {
let table : Map[String, Int] = { "a": 1, "b": 0xFF }
let text = "got \{shape} and \{scale}"
let raw =
#|literal ${not interpolated}
$|and \{interpolated}
guard scale > 0.0 else { fail("scale") }
match shape {
Circle(r) => 3.14159 * r * r
Rect(w, h) => w * h
}
let range = 1..=2
let pair = (1, 2).0
let bytes = b"\xFF\x00"
let ch = 'x'
let pattern = re"[a-z]+"
ignore(@json.parse(text))
let broken = "unterminated
let after = 1
}`
func TestEveryLineGetsExactlyOneEntry(t *testing.T) {
// The editor indexes the result by line number without checking, so a
// scanner that returned one entry fewer would draw every line below the
// gap in the wrong colours.
src := sample + "\n\n\ntrailing\n"
want := len(strings.Split(src, "\n"))
if got := len(moonbitlang.Highlight(src)); got != want {
t.Errorf("Highlight returned %d lines for %d lines of source", got, want)
}
}
func TestSpansAreInOrderAndDoNotOverlap(t *testing.T) {
// Spans are drawn in the order they arrive. Two out of order paint over
// each other, and nothing fails.
for number, spans := range moonbitlang.Highlight(sample) {
line := []rune(strings.Split(sample, "\n")[number])
previousEnd := 0
for _, span := range spans {
switch {
case span.Start < previousEnd:
t.Errorf("line %d: span %v starts before the previous one ended at %d", number+1, span, previousEnd)
case span.Start >= span.End:
t.Errorf("line %d: span %v is empty or inverted", number+1, span)
case span.End > len(line):
t.Errorf("line %d: span %v runs past the %d runes of the line", number+1, span, len(line))
}
previousEnd = span.End
}
}
}
func TestBrokenInputStillColours(t *testing.T) {
// Source under the cursor is invalid most of the time it is being typed.
broken := []string{
`let x = "`,
`let x = '`,
`let x = b"\`,
`fn (`,
`#`,
`#|`,
`$|`,
`@`,
`@/`,
`.`,
`..`,
`1.`,
`0x`,
`re"`,
`}}}`,
`let x = 1e`,
`let x = 1e-`,
`~`,
`let x~`,
}
for _, src := range broken {
spans := moonbitlang.Highlight(src)
if len(spans) != 1 {
t.Errorf("Highlight(%q) returned %d lines, want 1", src, len(spans))
}
}
}
func TestNothingCarriesOntoTheNextLine(t *testing.T) {
// This is the property that makes MoonBit's scanner stateless: no literal
// may reach the next line, so a stray quote must not paint the rest of the
// file. Every other editor in this family would carry here.
//
// Today the carry type is empty, so this cannot fail — and that is why it
// is written down. It is the guard on the type: a later change that gives
// carry a field has to keep every one of these openers from reaching the
// line below, and this is where it finds out that it did not.
openers := []string{`"`, `'`, `b"`, `b'`, `re"`, `#|`, `$|`, `#deprecated(`, `//`}
for _, opener := range openers {
src := "let a = " + opener + "\nfn main {\n println(\"hi\")\n}"
lines := moonbitlang.Highlight(src)
second := withText([]rune("fn main {"), lines[1])
if got, ok := find(second, "fn"); !ok || got.class != syntax.ClassKeyword {
t.Errorf("after a line opening with %q, fn on the next line is %v, want a keyword", opener, second)
}
}
}
func TestAnEmptyDocumentIsOneEmptyLine(t *testing.T) {
if got := moonbitlang.Highlight(""); len(got) != 1 || len(got[0]) != 0 {
t.Errorf("Highlight(\"\") = %v, want one line with no spans", got)
}
}
func TestCRLFColoursTheSameAsLF(t *testing.T) {
unix := moonbitlang.Highlight("fn main {\n println(\"hi\")\n}")
windows := moonbitlang.Highlight("fn main {\r\n println(\"hi\")\r\n}")
if len(unix) != len(windows) {
t.Fatalf("CRLF gave %d lines, LF gave %d", len(windows), len(unix))
}
for i := range unix {
if len(unix[i]) != len(windows[i]) {
t.Errorf("line %d: CRLF gave %v, LF gave %v", i+1, windows[i], unix[i])
}
}
}
// --- one case per construct -------------------------------------------------
func TestConstructs(t *testing.T) {
cases := []struct {
name string
src string
text string
class syntax.Class
}{
{"line comment", `let x = 1 // why`, `// why`, syntax.ClassComment},
{"doc comment", `/// Adds two numbers.`, `/// Adds two numbers.`, syntax.ClassComment},
{"section marker", `///|`, `///|`, syntax.ClassComment},
{"comment wins over division", `// a / b`, `// a / b`, syntax.ClassComment},
{"attribute", `#deprecated("use area")`, `#deprecated("use area")`, syntax.ClassAttribute},
{"namespaced attribute", `#custom.attribute(key="v")`, `#custom.attribute(key="v")`, syntax.ClassAttribute},
{"bare attribute", `#external`, `#external`, syntax.ClassAttribute},
{"raw multiline prefix", ` #|hello`, `#|`, syntax.ClassPunctuation},
{"raw multiline text", ` #|hello`, `hello`, syntax.ClassString},
{"interpolated multiline prefix", ` $|hi \{name}`, `$|`, syntax.ClassPunctuation},
{"interpolated multiline text", ` $|hi \{name}`, `hi \{name}`, syntax.ClassString},
{"string", `let s = "hi"`, `"hi"`, syntax.ClassString},
{"string stops at its closing quote", `let s = "hi" + name`, `"hi"`, syntax.ClassString},
{"code after a string is still code", `let s = "hi" + name`, `name`, syntax.ClassIdentifier},
{"char stops at its closing quote", `let c = 'x' + 1`, `'x'`, syntax.ClassChar},
{"code after a char is still code", `let c = 'x' + 1`, `1`, syntax.ClassNumber},
{"empty string", `let s = ""`, `""`, syntax.ClassString},
{"string with interpolation", `let s = "a \{b} c"`, `"a \{b} c"`, syntax.ClassString},
{"string with escaped quote", `let s = "a \" b"`, `"a \" b"`, syntax.ClassString},
{"bytes literal", `let b = b"\xFF"`, `b"\xFF"`, syntax.ClassString},
{"regex literal", `let r = re"[a-z]+"`, `re"[a-z]+"`, syntax.ClassString},
{"char literal", `let c = 'x'`, `'x'`, syntax.ClassChar},
{"escaped char literal", `let c = '\n'`, `'\n'`, syntax.ClassChar},
{"byte literal", `let c = b'x'`, `b'x'`, syntax.ClassChar},
{"decimal", `let n = 1_000`, `1_000`, syntax.ClassNumber},
{"hexadecimal", `let n = 0xFF_FF`, `0xFF_FF`, syntax.ClassNumber},
{"octal", `let n = 0o17`, `0o17`, syntax.ClassNumber},
{"binary", `let n = 0b1010`, `0b1010`, syntax.ClassNumber},
{"double", `let n = 1.5`, `1.5`, syntax.ClassNumber},
{"double with a trailing point", `let n = 1.`, `1.`, syntax.ClassNumber},
{"exponent", `let n = 1.5e-3`, `1.5e-3`, syntax.ClassNumber},
{"hex float", `let n = 0x1.8p3F`, `0x1.8p3F`, syntax.ClassNumber},
{"uint suffix", `let n = 42U`, `42U`, syntax.ClassNumber},
{"uint64 suffix", `let n = 42UL`, `42UL`, syntax.ClassNumber},
{"bigint suffix", `let n = 42N`, `42N`, syntax.ClassNumber},
{"float suffix", `let n = 1.0F`, `1.0F`, syntax.ClassNumber},
{"keyword", `pub fn area() -> Int {`, `fn`, syntax.ClassKeyword},
{"visibility keyword", `pub fn area() -> Int {`, `pub`, syntax.ClassKeyword},
{"try with a bang", `try! risky()`, `try!`, syntax.ClassKeyword},
{"guard with a bang", `guard! x`, `guard!`, syntax.ClassKeyword},
{"constant", `let ok = true`, `true`, syntax.ClassConstant},
{"option constructor", `Some(1)`, `Some`, syntax.ClassConstant},
{"result constructor", `Err("no")`, `Err`, syntax.ClassConstant},
{"builtin", `println("hi")`, `println`, syntax.ClassBuiltin},
{"builtin in a test", `assert_eq(1, 1)`, `assert_eq`, syntax.ClassBuiltin},
{"built-in type", `let n : Int = 1`, `Int`, syntax.ClassType},
{"generic type", `let m : Map[String, Int] = {}`, `Map`, syntax.ClassType},
{"a type nobody built in", `let p : Point = origin`, `Point`, syntax.ClassType},
{"a constructor of your own", `Circle(1.0)`, `Circle`, syntax.ClassType},
{"call", `area(shape)`, `area`, syntax.ClassFunction},
{"plain identifier", `let shape = other`, `other`, syntax.ClassIdentifier},
{"package name", `@json.parse(text)`, `@json`, syntax.ClassType},
{"nested package name", `@moonbitlang/core/builtin.foo()`, `@moonbitlang/core/builtin`, syntax.ClassType},
{"hyphenated package name", `@my-pkg.foo()`, `@my-pkg`, syntax.ClassType},
{"label", `fn greet(name~ : String)`, `name~`, syntax.ClassAttribute},
{"optional label", `fn greet(name~ : String = "x")`, `name~`, syntax.ClassAttribute},
{"method call", `xs.length()`, `length`, syntax.ClassFunction},
{"field access", `point.x`, `x`, syntax.ClassIdentifier},
{"tuple accessor dot", `pair.0`, `.`, syntax.ClassPunctuation},
{"tuple accessor index", `pair.0`, `0`, syntax.ClassNumber},
{"range operator", `for i in 1..=10 {`, `..`, syntax.ClassOperator},
{"pipe operator", `x |> f`, `|>`, syntax.ClassOperator},
{"arrow", `Circle(r) => r`, `=>`, syntax.ClassOperator},
{"colon is an operator rune", `Type::method`, `::`, syntax.ClassOperator},
{"brace", `fn main {`, `{`, syntax.ClassPunctuation},
}
for _, c := range cases {
t.Run(c.name, func(t *testing.T) {
assertClass(t, c.src, c.text, c.class)
})
}
}
func TestRangeStopsTheNumberBeforeIt(t *testing.T) {
// "Before .., an integer ends first, so 1..=2 begins with 1 and ..=". A
// scanner that swallowed any dot would read 1. as a double and miscolour
// every range in the file.
spans := colouredLine(t, `for i in 1..=10 {`)
if got, ok := find(spans, "1"); !ok || got.class != syntax.ClassNumber {
t.Errorf("in 1..=10, the 1 is %v, want a number on its own; got %v", got, spans)
}
if _, ok := find(spans, "1."); ok {
t.Errorf("in 1..=10, the scanner read 1. as a double: %v", spans)
}
}
// --- one case per thing the scanner deliberately refuses --------------------
func TestRefusals(t *testing.T) {
cases := []struct {
name string
why string
src string
text string
class syntax.Class
}{
{
name: "an interpolated expression is not code",
why: "finding where one ends needs the parser; a brace counter that got it wrong would end the string early",
src: `let s = "\{count + 1}"`,
text: `"\{count + 1}"`,
class: syntax.ClassString,
},
{
name: "a lower-case number suffix is not a suffix",
why: "the grammar says the suffixes are upper case, so 42u is 42 and then the name u",
src: `let n = 42u`,
text: `42`,
class: syntax.ClassNumber,
},
{
name: "a leading dot is never a number",
why: "MoonBit requires a digit before the point, so .5 is a dot and then a name",
src: `let n = .5`,
text: `.`,
class: syntax.ClassPunctuation,
},
{
name: "a keyword after a dot is a field name",
why: "dot-identifiers use the identifier case rules without consulting the keyword table, so .if is valid",
src: `config.if`,
text: `if`,
class: syntax.ClassIdentifier,
},
{
name: "a reserved word is not a keyword",
why: "move, ref and the rest are identifiers the compiler warns about; colouring them would deny a valid name",
src: `let ref = 1`,
text: `ref`,
class: syntax.ClassIdentifier,
},
{
name: "an enum constructor of your own is a type",
why: "nothing in the syntax separates Circle(1.0) from a type applied to arguments",
src: `Circle(1.0)`,
text: `Circle`,
class: syntax.ClassType,
},
{
name: "an unterminated literal stops at the line",
why: "a newline before the closing quote is an unterminated-literal error, so there is nothing to carry",
src: `let s = "oops`,
text: `"oops`,
class: syntax.ClassString,
},
{
name: "an upper-case name cannot form a label",
why: "the grammar says ASCII-uppercase identifiers and keywords cannot form labels",
src: `Foo~`,
text: `Foo`,
class: syntax.ClassType,
},
{
name: "a keyword cannot form a label",
why: "same rule; let~ is not a labelled argument called let",
src: `let~`,
text: `let`,
class: syntax.ClassKeyword,
},
{
name: "b is only a prefix when the quote touches it",
why: "otherwise the variable b in `b + 1` would open a literal",
src: `b + 1`,
text: `b`,
class: syntax.ClassIdentifier,
},
{
name: "a package part must follow the slash",
why: "@a/2 is a package and then a division, not a package part called 2",
src: `@a/2`,
text: `@a`,
class: syntax.ClassType,
},
{
name: "a doc comment is coloured like any other comment",
why: "turbo-core's Class set is closed and has one comment class, which is what lets one theme colour every language",
src: `/// docs`,
text: `/// docs`,
class: syntax.ClassComment,
},
}
for _, c := range cases {
t.Run(c.name, func(t *testing.T) {
assertClass(t, c.src, c.text, c.class)
})
}
}
// A string *nested inside* an interpolation ends the outer literal, because
// the scanner takes the first unescaped quote as the closer. The grammar says
// otherwise — "braces inside nested literals do not affect matching" — so this
// is the precise shape of what the scanner gives up by not parsing, and it is
// pinned here rather than described loosely.
//
// The spans stay in order and never overlap, so nothing downstream breaks; the
// cost is that text inside the nested literal may take a different colour.
func TestAStringInsideAnInterpolationEndsTheOuterLiteral(t *testing.T) {
// The ordinary case is one span, which is what almost every interpolation
// in real MoonBit looks like.
if spans := colouredLine(t, `let s = "a \{b} c"`); len(spans) != 4 {
t.Errorf(`"a \{b} c" gave %v, want the whole literal as one span`, spans)
}
// With a nested literal it is not one span, and the inside of that literal
// is not coloured as a string.
spans := colouredLine(t, `let s = "a \{f("x")} c"`)
if got, ok := find(spans, "x"); !ok || got.class != syntax.ClassIdentifier {
t.Errorf(`"a \{f("x")} c" coloured the nested literal's contents as %v, want the documented identifier`, spans)
}
// Whatever it does colour, the invariants hold.
previousEnd := 0
for _, span := range moonbitlang.Highlight(`let s = "a \{f("x")} c"`)[0] {
if span.Start < previousEnd {
t.Errorf("spans overlap: %v", spans)
}
previousEnd = span.End
}
}
func TestANonASCIIIdentifierIsLeftUncoloured(t *testing.T) {
// MoonBit allows CJK and other ranges in identifiers; turbo-core's rune
// predicates are ASCII. Such a name is stepped over rather than guessed at,
// which is a boundary worth knowing rather than a defect to hide.
spans := colouredLine(t, `let 名前 = 1`)
if _, ok := find(spans, "名前"); ok {
t.Errorf("a CJK identifier was coloured: %v", spans)
}
if got, ok := find(spans, "let"); !ok || got.class != syntax.ClassKeyword {
t.Errorf("the rest of the line stopped colouring: %v", spans)
}
}
func TestHighlightIsWhatTheRegistryUses(t *testing.T) {
moonbitlang.Register()
spans := syntax.Highlight(moonbitlang.Language, "fn main {\n")
if len(spans) == 0 || len(spans[0]) == 0 {
t.Fatalf("syntax.Highlight gave nothing for MoonBit: %v", spans)
}
if spans[0][0].Class != syntax.ClassKeyword {
t.Errorf("the registered highlighter coloured fn as %s, want a keyword", spans[0][0].Class)
}
}
|