add BuildNamed

README.md

@@ -44,6 +44,7 @@ Following builders are implemented right now. API document and examples are prov
 * [DeleteBuilder](https://godoc.org/github.com/huandu/go-sqlbuilder#DeleteBuilder): Builder for DELETE.
 * [Buildf](https://godoc.org/github.com/huandu/go-sqlbuilder#Buildf): Freestyle builder using `fmt.Sprintf`-like syntax.
 * [Build](https://godoc.org/github.com/huandu/go-sqlbuilder#Build): Advanced freestyle builder using special syntax defined in [Args#Compile](https://godoc.org/github.com/huandu/go-sqlbuilder#Args.Compile).
+* [BuildNamed](https://godoc.org/github.com/huandu/go-sqlbuilder#BuildNamed): Advanced freestyle builder using `${key}` to refer the value of a map by key.
 
 ### Using `Struct` as a light weight ORM ###
 

args.go

@@ -17,6 +17,7 @@ type Args struct {
 	args         []interface{}
 	namedArgs    map[string]int
 	sqlNamedArgs map[string]int
+	onlyNamed    bool
 }
 
 // Add adds an arg to Args and returns a placeholder.
@@ -89,9 +90,9 @@ func (args *Args) Compile(format string) (query string, values []interface{}) {
 			format = format[1:]
 		} else if format[0] == '{' {
 			format, values = args.compileNamed(buf, format, values)
-		} else if '0' <= format[0] && format[0] <= '9' {
+		} else if !args.onlyNamed && '0' <= format[0] && format[0] <= '9' {
 			format, values, offset = args.compileDigits(buf, format, values, offset)
-		} else if format[0] == '?' {
+		} else if !args.onlyNamed && format[0] == '?' {
 			format, values, offset = args.compileSuccessive(buf, format[1:], values, offset)
 		}
 

builder.go

@@ -44,7 +44,7 @@ func Buildf(format string, arg ...interface{}) Builder {
 }
 
 // Build creates a Builder from a format string.
-// The format string uses a special syntax to represent arguments.
+// The format string uses special syntax to represent arguments.
 // See doc in `Args#Compile` for syntax details.
 func Build(format string, arg ...interface{}) Builder {
 	args := &Args{}
@@ -59,3 +59,21 @@ func Build(format string, arg ...interface{}) Builder {
 		args: values,
 	}
 }
+
+// BuildNamed creates a Builder from a format string.
+// The format string uses `${key}` to refer the value of named by key.
+func BuildNamed(format string, named map[string]interface{}) Builder {
+	args := &Args{
+		onlyNamed: true,
+	}
+
+	for n, v := range named {
+		args.Add(Named(n, v))
+	}
+
+	sql, values := args.Compile(format)
+	return &compiledBuilder{
+		sql:  sql,
+		args: values,
+	}
+}

builder_test.go

@@ -4,6 +4,7 @@
 package sqlbuilder
 
 import (
+	"database/sql"
 	"fmt"
 )
 
@@ -36,3 +37,21 @@ func ExampleBuild() {
 	// EXPLAIN SELECT id FROM user WHERE status IN (?, ?) LEFT JOIN SELECT * FROM banned WHERE created_at > ? AND state IN (?, ?, ?) AND modified_at BETWEEN ? AND ?
 	// [1 2 1514458225 3 4 5 1514458225 1514544625]
 }
+
+func ExampleBuildNamed() {
+	b := BuildNamed("SELECT * FROM ${table} WHERE status IN (${status}) AND name LIKE ${name} AND created_at > ${time} AND modified_at < ${time} + 86400",
+		map[string]interface{}{
+			"time":   sql.Named("start", 1234567890),
+			"status": List([]int{1, 2, 5}),
+			"name":   "Huan%",
+			"table":  Raw("user"),
+		})
+	sql, args := b.Build()
+
+	fmt.Println(sql)
+	fmt.Println(args)
+
+	// Output:
+	// SELECT * FROM user WHERE status IN (?, ?, ?) AND name LIKE ? AND created_at > @start AND modified_at < @start + 86400
+	// [1 2 5 Huan% {{} start 1234567890}]
+}