Participle internal hang?

[drew-512]

Hi participle friends and mr @alecthomas,

• Love participle and have been using for 2 years now and tell anyone who wants to listen about it.
• Trying to troubleshoot participle v2.1.1 in a project approaching alpha
• Making an INI parser based on the example in "_examples"
• troubleshooting ParseBytes(), and unclear if it's the grammar or participle -- seeing a full hang, no console / debug output, M1 cpu churning around 30%
• No doubt there are improvements or fixes -- your time and suggestions are much appreciated and curious what is happening under the hood.
• ParseINI()(below) is called with:

a = "a"
b = 123  # first comment

# A comment
[numbers]
a = 10.3  ; a comment
b = 20

func ParseINI(filepath string, text []byte) (*INI, error) {
	return iniParser.ParseBytes(filepath, text)
}

var (
	iniLexer = lexer.MustSimple([]lexer.SimpleRule{
		{`Ident`, `[A-Za-z\._][A-Za-z0-9_-\.]*`},
		//{`Ident`, `[^\s]*`},
		{`String`, `"(?:\\.|[^"])*"`},
		{`Number`, `\d+(?:\.\d+)?`},
		{`Punct`, `[][=]`},
		{"comment", `[#;][^\n]*`},
		{"whitespace", `\s+`},
	})
	iniParser = participle.MustBuild[INI](
		participle.Lexer(iniLexer),
		participle.Unquote("String"),
	)
)

type LexerState struct {
	Location lexer.Position
}

type INI struct {
	LexerState

	Sections []*Section `@@*`
}

type Section struct {
	LexerState

	Header  *Entry   `( "[" @@ "]" )?`
	Entries []*Entry `@@*`
}

type List struct {
	lexer.Position

	Elements []*Value `"[" ( @@ ( ","? @@ )* )? "]"`
}

type Entry struct {
	LexerState

	LHS *Value `@@* "="`
	RHS *Value `@@*`
}

type Value struct {
	LexerState

	Args   []string `(@Ident)*`
	Number *float64 `| @Number`
	List   *List    `| @@`
}

[alecthomas]

I'm glad you're enjoying Participle. I don't know how you're invoking this, but this code panics immediately for me:

panic: Root.0: error parsing regexp: invalid character class range: `_-\.`

goroutine 1 [running]:
github.com/alecthomas/participle/v2/lexer.MustSimple(...)
	/Users/alec/go/pkg/mod/github.com/alecthomas/participle/[email protected]/lexer/simple.go:15
main.init()
	/Users/alec/dev/participle/foo/main.go:26 +0x250
exit status 2

[drew-512]

blinks several times

[drew-512]

Ah yes, I had initially posted:

type Entry struct {
	LexerState

	LHS *Value `@@* "="`
	RHS *Value `@@*`
}

and fixed to:

type Entry struct {
	LexerState

	LHS *Value `@@ "="`
	RHS *Value `@@`
}

and so now I am seeing panic: Root.0: error parsing regexp: invalid character class range: _-.`` as you described.