qb: extracted function from cmp

qb/cmp.go

@@ -28,49 +28,8 @@ const (
 type Cmp struct {
 	op     op
 	column string
-	fn     string
-	names  []string
-}
-
-// Func wraps comparator value with a custom function, fn is a function name,
-// names are function arguments' bind names. For instance function:
-//
-//    CREATE FUNCTION somefunction(somearg int, anotherarg text)
-//
-// can be used like this:
-//
-//    stmt, names := qb.Select("table").
-//        Where(qb.Eq("t").Func("somefunction", "somearg", "anotherarg")).
-//        ToCql()
-//
-//    q := gocqlx.Query(session.Query(stmt), names).BindMap(qb.M{
-//        "somearg": 1,
-//        "anotherarg": "text",
-//    })
-func (c Cmp) Func(fn string, names ...string) Cmp {
-	c.fn = fn
-	c.names = names
-	return c
-}
-
-// MinTimeuuid sets minTimeuuid(?) compare value.
-func (c Cmp) MinTimeuuid(name string) Cmp {
-	return c.Func("minTimeuuid", name)
-}
-
-// MaxTimeuuid sets maxTimeuuid(?) compare value.
-func (c Cmp) MaxTimeuuid(name string) Cmp {
-	return c.Func("maxTimeuuid", name)
-}
-
-// Now sets now() compare value.
-func (c Cmp) Now() Cmp {
-	return c.Func("now")
-}
-
-// Token sets Token(?,?...) compare value.
-func (c Cmp) Token(names ...string) Cmp {
-	return c.Func("token", names...)
+	name   string
+	fn     *Func
 }
 
 func (c Cmp) writeCql(cql *bytes.Buffer) (names []string) {
@@ -94,19 +53,15 @@ func (c Cmp) writeCql(cql *bytes.Buffer) (names []string) {
 		cql.WriteString(" CONTAINS ")
 	}
 
-	if c.fn == "" {
+	if c.fn == nil {
 		cql.WriteByte('?')
-		if c.names == nil {
+		if c.name == "" {
 			names = append(names, c.column)
 		} else {
-			names = append(names, c.names...)
+			names = append(names, c.name)
 		}
 	} else {
-		cql.WriteString(c.fn)
-		cql.WriteByte('(')
-		placeholders(cql, len(c.names))
-		cql.WriteByte(')')
-		names = append(names, c.names...)
+		names = append(names, c.fn.writeCql(cql)...)
 	}
 
 	return
@@ -125,7 +80,16 @@ func EqNamed(column, name string) Cmp {
 	return Cmp{
 		op:     eq,
 		column: column,
-		names:  []string{name},
+		name:   name,
+	}
+}
+
+// EqFunc produces column=someFunc(?...).
+func EqFunc(column string, fn *Func) Cmp {
+	return Cmp{
+		op:     eq,
+		column: column,
+		fn:     fn,
 	}
 }
 
@@ -142,7 +106,16 @@ func LtNamed(column, name string) Cmp {
 	return Cmp{
 		op:     lt,
 		column: column,
-		names:  []string{name},
+		name:   name,
+	}
+}
+
+// LtFunc produces column<someFunc(?...).
+func LtFunc(column string, fn *Func) Cmp {
+	return Cmp{
+		op:     lt,
+		column: column,
+		fn:     fn,
 	}
 }
 
@@ -159,7 +132,16 @@ func LtOrEqNamed(column, name string) Cmp {
 	return Cmp{
 		op:     leq,
 		column: column,
-		names:  []string{name},
+		name:   name,
+	}
+}
+
+// LtOrEqFunc produces column<=someFunc(?...).
+func LtOrEqFunc(column string, fn *Func) Cmp {
+	return Cmp{
+		op:     leq,
+		column: column,
+		fn:     fn,
 	}
 }
 
@@ -176,7 +158,16 @@ func GtNamed(column, name string) Cmp {
 	return Cmp{
 		op:     gt,
 		column: column,
-		names:  []string{name},
+		name:   name,
+	}
+}
+
+// GtFunc produces column>someFunc(?...).
+func GtFunc(column string, fn *Func) Cmp {
+	return Cmp{
+		op:     gt,
+		column: column,
+		fn:     fn,
 	}
 }
 
@@ -193,7 +184,16 @@ func GtOrEqNamed(column, name string) Cmp {
 	return Cmp{
 		op:     geq,
 		column: column,
-		names:  []string{name},
+		name:   name,
+	}
+}
+
+// GtFunc produces column>=someFunc(?...).
+func GtOrEqFunc(column string, fn *Func) Cmp {
+	return Cmp{
+		op:     geq,
+		column: column,
+		fn:     fn,
 	}
 }
 
@@ -210,7 +210,7 @@ func InNamed(column, name string) Cmp {
 	return Cmp{
 		op:     in,
 		column: column,
-		names:  []string{name},
+		name:   name,
 	}
 }
 
@@ -227,7 +227,7 @@ func ContainsNamed(column, name string) Cmp {
 	return Cmp{
 		op:     cnt,
 		column: column,
-		names:  []string{name},
+		name:   name,
 	}
 }
 

qb/cmp_test.go

@@ -93,29 +93,24 @@ func TestCmp(t *testing.T) {
 
 		// Functions
 		{
-			C: Eq("eq").Func("fn", "arg0", "arg1"),
+			C: EqFunc("eq", Fn("fn", "arg0", "arg1")),
 			S: "eq=fn(?,?)",
 			N: []string{"arg0", "arg1"},
 		},
 		{
-			C: Eq("eq").MaxTimeuuid("arg0"),
+			C: EqFunc("eq", MaxTimeuuid("arg0")),
 			S: "eq=maxTimeuuid(?)",
 			N: []string{"arg0"},
 		},
 		{
-			C: Eq("eq").MinTimeuuid("arg0"),
+			C: EqFunc("eq", MinTimeuuid("arg0")),
 			S: "eq=minTimeuuid(?)",
 			N: []string{"arg0"},
 		},
 		{
-			C: Eq("eq").Now(),
+			C: EqFunc("eq", Now()),
 			S: "eq=now()",
 		},
-		{
-			C: Eq("eq").Token("arg0", "arg1"),
-			S: "eq=token(?,?)",
-			N: []string{"arg0", "arg1"},
-		},
 	}
 
 	buf := bytes.Buffer{}

qb/func.go

@@ -0,0 +1,51 @@
+// Copyright (C) 2017 ScyllaDB
+// Use of this source code is governed by a ALv2-style
+// license that can be found in the LICENSE file.
+
+package qb
+
+import "bytes"
+
+// Functions reference:
+// https://cassandra.apache.org/doc/latest/cql/functions.html
+
+// Func is a custom database function invocation that can be use in a comparator
+// or update statement.
+type Func struct {
+	// function name
+	Name string
+	// name of the function parameters
+	ParamNames []string
+}
+
+func (f *Func) writeCql(cql *bytes.Buffer) (names []string) {
+	cql.WriteString(f.Name)
+	cql.WriteByte('(')
+	placeholders(cql, len(f.ParamNames))
+	cql.WriteByte(')')
+	names = append(names, f.ParamNames...)
+	return
+}
+
+// Fn creates Func.
+func Fn(name string, paramNames ...string) *Func {
+	return &Func{
+		Name:       name,
+		ParamNames: paramNames,
+	}
+}
+
+// MinTimeuuid produces minTimeuuid(?).
+func MinTimeuuid(name string) *Func {
+	return Fn("minTimeuuid", name)
+}
+
+// MaxTimeuuid produces maxTimeuuid(?).
+func MaxTimeuuid(name string) *Func {
+	return Fn("maxTimeuuid", name)
+}
+
+// Now produces now().
+func Now() *Func {
+	return Fn("now")
+}

qb/token.go

@@ -9,110 +9,72 @@ import (
 	"strings"
 )
 
+// TokenBuilder helps implement pagination using token function.
+type TokenBuilder []string
+
 // Token creates a new TokenBuilder.
 func Token(columns ...string) TokenBuilder {
 	return TokenBuilder(columns)
 }
 
-// TokenBuilder helps implement pagination using token function.
-type TokenBuilder []string
-
 // Eq produces token(column)=token(?).
 func (t TokenBuilder) Eq() Cmp {
-	return Cmp{
-		op:     eq,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  t,
-	}
+	return t.cmp(eq, nil)
 }
 
 // EqNamed produces token(column)=token(?) with a custom parameter name.
 func (t TokenBuilder) EqNamed(names ...string) Cmp {
-	return Cmp{
-		op:     eq,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  names,
-	}
+	return t.cmp(eq, names)
 }
 
 // Lt produces token(column)<token(?).
 func (t TokenBuilder) Lt() Cmp {
-	return Cmp{
-		op:     lt,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  t,
-	}
+	return t.cmp(lt, nil)
 }
 
 // LtNamed produces token(column)<token(?) with a custom parameter name.
 func (t TokenBuilder) LtNamed(names ...string) Cmp {
-	return Cmp{
-		op:     lt,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  names,
-	}
+	return t.cmp(lt, names)
 }
 
 // LtOrEq produces token(column)<=token(?).
 func (t TokenBuilder) LtOrEq() Cmp {
-	return Cmp{
-		op:     leq,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  t,
-	}
+	return t.cmp(leq, nil)
 }
 
 // LtOrEqNamed produces token(column)<=token(?) with a custom parameter name.
 func (t TokenBuilder) LtOrEqNamed(names ...string) Cmp {
-	return Cmp{
-		op:     leq,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  names,
-	}
+	return t.cmp(leq, names)
 }
 
 // Gt produces token(column)>token(?).
 func (t TokenBuilder) Gt() Cmp {
-	return Cmp{
-		op:     gt,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  t,
-	}
+	return t.cmp(gt, nil)
 }
 
 // GtNamed produces token(column)>token(?) with a custom parameter name.
 func (t TokenBuilder) GtNamed(names ...string) Cmp {
-	return Cmp{
-		op:     gt,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  names,
-	}
+	return t.cmp(gt, names)
 }
 
 // GtOrEq produces token(column)>=token(?).
 func (t TokenBuilder) GtOrEq() Cmp {
-	return Cmp{
-		op:     geq,
-		fn:     "token",
-		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  t,
-	}
+	return t.cmp(geq, nil)
 }
 
 // GtOrEqNamed produces token(column)>=token(?) with a custom parameter name.
 func (t TokenBuilder) GtOrEqNamed(names ...string) Cmp {
+	return t.cmp(geq, names)
+}
+
+func (t TokenBuilder) cmp(op op, names []string) Cmp {
+	s := names
+	if s == nil {
+		s = t
+	}
 	return Cmp{
-		op:     geq,
-		fn:     "token",
+		op:     op,
 		column: fmt.Sprint("token(", strings.Join(t, ","), ")"),
-		names:  names,
+		fn:     Fn("token", s...),
 	}
 }