Sort statements

krab/sql_statement.go

@@ -2,6 +2,7 @@ package krab
 
 import (
 	"io"
+	"sort"
 	"strings"
 
 	"github.com/hashicorp/hcl/v2"
@@ -18,17 +19,47 @@ type SQLStatement string
 // SQLStatements represents list of raw SQL statements.
 type SQLStatements []SQLStatement
 
+// Append adds new SQL statement to the list from object that satisfies ToSQL interface.
+func (s *SQLStatements) Append(sql ToSQL) {
+	sb := &strings.Builder{}
+	sql.ToSQL(sb)
+	*s = append(*s, SQLStatement(sb.String()))
+}
+
 // SQLStatementsSorter sorts SQLStatement by the order how they are defined in a file.
 type SQLStatementsSorter struct {
 	Statements SQLStatements
 	Bytes      []int
 }
 
-// Append adds new SQL statement to the list from object that satisfies ToSQL interface.
-func (s *SQLStatements) Append(sql ToSQL) {
-	sb := &strings.Builder{}
-	sql.ToSQL(sb)
-	*s = append(*s, SQLStatement(sb.String()))
+// Len is the number of elements in the collection.
+func (s *SQLStatementsSorter) Len() int {
+	return len(s.Statements)
+}
+
+// Less reports whether the element with index i
+// must sort before the element with index j.
+//
+// If both Less(i, j) and Less(j, i) are false,
+// then the elements at index i and j are considered equal.
+// Sort may place equal elements in any order in the final result,
+// while Stable preserves the original input order of equal elements.
+//
+// Less must describe a transitive ordering:
+//  - if both Less(i, j) and Less(j, k) are true, then Less(i, k) must be true as well.
+//  - if both Less(i, j) and Less(j, k) are false, then Less(i, k) must be false as well.
+//
+// Note that floating-point comparison (the < operator on float32 or float64 values)
+// is not a transitive ordering when not-a-number (NaN) values are involved.
+// See Float64Slice.Less for a correct implementation for floating-point values.
+func (s *SQLStatementsSorter) Less(i int, j int) bool {
+	return s.Bytes[i] < s.Bytes[j]
+}
+
+// Swap swaps the elements with indexes i and j.
+func (s *SQLStatementsSorter) Swap(i int, j int) {
+	s.Bytes[i], s.Bytes[j] = s.Bytes[j], s.Bytes[i]
+	s.Statements[i], s.Statements[j] = s.Statements[j], s.Statements[i]
 }
 
 // Insert ToSQL at given range.
@@ -39,7 +70,6 @@ func (s *SQLStatementsSorter) Insert(r hcl.Range, sql ToSQL) {
 
 // Sort sorts statements by byte range.
 func (s *SQLStatementsSorter) Sort() SQLStatements {
-	ret := make(SQLStatements, len(s.Statements))
-	copy(ret, s.Statements) // TODO: replace with actual sort
-	return ret
+	sort.Sort(s)
+	return s.Statements
 }