1 files changed, 107 insertions, 0 deletions
diff --git a/gemtext/parse_line.go b/gemtext/parse_line.go
new file mode 100644
index 0000000..39187a8
--- /dev/null
+++ b/gemtext/parse_line.go
@@ -0,0 +1,107 @@
+package gemtext
+
+import "bytes"
+
+// ParseLine parses a single line (including the trailing \n) into a gemtext.Line.
+func ParseLine(line []byte) Line {
+	if len(line) == 0 {
+		return nil
+	}
+
+	switch line[0] {
+	case '=':
+		if len(line) == 1 || line[1] != '>' {
+			break
+		}
+		return parseLinkLine(line)
+	case '`':
+		if len(line) < 3 || line[1] != '`' || line[2] != '`' {
+			break
+		}
+		return parsePreformatToggleLine(line)
+	case '#':
+		level := 1
+		if len(line) > 1 && line[1] == '#' {
+			level += 1
+			if len(line) > 2 && line[2] == '#' {
+				level += 1
+			}
+		}
+		return parseHeadingLine(level, line)
+	case '*':
+		if len(line) == 1 || line[1] != ' ' {
+			break
+		}
+		return parseListItemLine(line)
+	case '>':
+		return parseQuoteLine(line)
+	}
+
+	return TextLine{raw: line}
+}
+
+func parseLinkLine(raw []byte) LinkLine {
+	line := LinkLine{raw: raw}
+
+	// move past =>[<whitespace>]
+	raw = bytes.TrimLeft(raw[2:], " \t")
+
+	// find the next space or tab
+	spIdx := bytes.IndexByte(raw, ' ')
+	tbIdx := bytes.IndexByte(raw, '\t')
+	idx := spIdx
+	if idx == -1 {
+		idx = tbIdx
+	}
+	if tbIdx >= 0 && tbIdx < idx {
+		idx = tbIdx
+	}
+
+	if idx < 0 {
+		line.url = bytes.TrimRight(raw, "\r\n")
+		return line
+	}
+
+	line.url = raw[:idx]
+	raw = raw[idx+1:]
+
+	label := bytes.TrimRight(bytes.TrimLeft(raw, " \t"), "\r\n")
+	if len(label) > 0 {
+		line.label = label
+	}
+
+	return line
+}
+
+func parsePreformatToggleLine(raw []byte) PreformatToggleLine {
+	line := PreformatToggleLine{raw: raw}
+
+	raw = bytes.TrimRight(raw[3:], "\r\n")
+	if len(raw) > 0 {
+		line.altText = raw
+	}
+
+	return line
+}
+
+func parseHeadingLine(level int, raw []byte) HeadingLine {
+	return HeadingLine{
+		raw:      raw,
+		lineType: LineTypeHeading1 - 1 + LineType(level),
+		body:     bytes.TrimRight(bytes.TrimLeft(raw[level:], " \t"), "\r\n"),
+	}
+}
+
+func parseListItemLine(raw []byte) ListItemLine {
+	return ListItemLine{
+		raw:  raw,
+		body: bytes.TrimRight(raw[2:], "\r\n"),
+	}
+}
+
+func parseQuoteLine(raw []byte) QuoteLine {
+	return QuoteLine{
+		raw:  raw,
+		body: bytes.TrimRight(raw[1:], "\r\n"),
+	}
+}