feat: add strings package

Author: ChrisRx

strings/strings.go

@@ -0,0 +1,69 @@
+package strings
+
+import (
+	"bufio"
+	"bytes"
+	"cmp"
+	"strings"
+	"unicode/utf8"
+)
+
+// Dedent attempts to determine the indent-level from the first non-empty line,
+// and trims the indents from all lines.
+func Dedent(s string) string {
+	scanner := bufio.NewScanner(strings.NewReader(s))
+	var indent []byte
+	var b bytes.Buffer
+	for scanner.Scan() {
+		line := scanner.Bytes()
+		if len(line) == 0 {
+			continue
+		}
+		if indent == nil {
+			indent = detect(line).Bytes()
+		}
+		line = bytes.TrimPrefix(line, indent)
+		if len(bytes.TrimSpace(line)) == 0 {
+			continue
+		}
+		b.Write(line)
+		b.WriteRune('\n')
+	}
+	return b.String()
+}
+
+func detect(line []byte) (indent indent) {
+	if len(line) == 0 {
+		return
+	}
+	switch rune(line[0]) {
+	case '\t':
+		indent.c = rune(line[0])
+		indent.n += 1
+	case ' ':
+		indent.c = rune(line[0])
+		indent.n += 1
+	default:
+		return
+	}
+	for _, r := range line[1:] {
+		if rune(r) != indent.c {
+			return
+		}
+		indent.n += 1
+	}
+	return
+}
+
+type indent struct {
+	c rune
+	n int
+}
+
+func (i indent) Len() int {
+	return cmp.Or(i.n, 0)
+}
+
+func (i indent) Bytes() []byte {
+	return bytes.Repeat(utf8.AppendRune(nil, i.c), i.n)
+}

strings/strings_test.go

@@ -0,0 +1,28 @@
+package strings
+
+import (
+	"testing"
+
+	"go.chrisrx.dev/x/assert"
+)
+
+func TestDedent(t *testing.T) {
+	s := Dedent(`
+		SELECT
+			*
+		FROM
+			table t1
+		WHERE
+			status = 'ok'
+			AND something <> 'lol'
+	`)
+
+	assert.Equal(t, `SELECT
+	*
+FROM
+	table t1
+WHERE
+	status = 'ok'
+	AND something <> 'lol'
+`, s)
+}