retangled-go/markdown/attributes.go

// package markdown includes basic markdown parsing for reTangleD.
// The interface is subject to change at any time
// It is mostly an implementation of the [attributes CommonMark proposal](https://talk.commonmark.org/t/consistent-attribute-syntax/272) at the moment
package markdown

import (
	"strings"
)

// Attributes contains parsed Markdown attributes from the form:
// `{#id .class file=main.c other="test okay"}`
type Attributes struct {
	ID string
	Classes []string
	// Other includes attributes in the format file=main.c
	Other map[string]string
}

// GetAttributes finds the attributes from a Markdown line
// Returns a blank Attributes struct if there are no attributes
func GetAttributes(line string) (Attributes) {
	attrs := ""
	if strings.Index(line, "{") != -1 {
		attrs = line[strings.Index(line, "{"):]
	}

	// If it only contains `{}` and nothing more, or not even that
	if len(attrs) < 2 {
		return Attributes{}
	}

	if attrs[0] != '{' || attrs[len(attrs)-1] != '}' {
		return Attributes{}
	}

	// proceed with all the attrs without { and }
	return attribute(attrs[1:len(attrs)-1])
}

// Attribute parses attributes into an Attributes struct
// TODO: handle "this format" (so don't split by spaces)
func attribute(text string) (Attributes) {
	attrs := strings.Split(text, " ")

	result := Attributes{}
	result.Other = map[string]string{}
	for _, attr := range attrs {
		switch attr[0] {
		case '#':
			result.ID = attr[1:]
		case '.':
			result.Classes = append(result.Classes, attr[1:])
		default:
			if strings.Index(attr, "=") > 0 {
				result.Other[strings.Split(attr, "=")[0]] = strings.Split(attr, "=")[1]
			}
		}
	}

	return result
}