qb: cmp

qb/cmp.go

@@ -0,0 +1,171 @@
+package qb
+
+import "bytes"
+
+type op byte
+
+const (
+	eq op = iota
+	lt
+	leq
+	gt
+	geq
+	in
+	cnt
+)
+
+type Cmp struct {
+	op     op
+	column string
+	name   string
+}
+
+func (cmp Cmp) writeCql(cql *bytes.Buffer) string {
+	cql.WriteString(cmp.column)
+	switch cmp.op {
+	case eq:
+		cql.WriteByte('=')
+	case lt:
+		cql.WriteByte('<')
+	case leq:
+		cql.WriteByte('<')
+		cql.WriteByte('=')
+	case gt:
+		cql.WriteByte('>')
+	case geq:
+		cql.WriteByte('>')
+		cql.WriteByte('=')
+	case in:
+		cql.WriteString(" IN ")
+	case cnt:
+		cql.WriteString(" CONTAINS ")
+	}
+	cql.WriteByte('?')
+
+	return cmp.name
+}
+
+func Eq(column string) Cmp {
+	return Cmp{
+		op:     eq,
+		column: column,
+		name:   column,
+	}
+}
+
+func EqNamed(column, name string) Cmp {
+	return Cmp{
+		op:     eq,
+		column: column,
+		name:   name,
+	}
+}
+
+func Lt(column string) Cmp {
+	return Cmp{
+		op:     lt,
+		column: column,
+		name:   column,
+	}
+}
+
+func LtNamed(column, name string) Cmp {
+	return Cmp{
+		op:     lt,
+		column: column,
+		name:   name,
+	}
+}
+
+func LtOrEq(column string) Cmp {
+	return Cmp{
+		op:     leq,
+		column: column,
+		name:   column,
+	}
+}
+
+func LtOrEqNamed(column, name string) Cmp {
+	return Cmp{
+		op:     leq,
+		column: column,
+		name:   name,
+	}
+}
+
+func Gt(column string) Cmp {
+	return Cmp{
+		op:     gt,
+		column: column,
+		name:   column,
+	}
+}
+
+func GtNamed(column, name string) Cmp {
+	return Cmp{
+		op:     gt,
+		column: column,
+		name:   name,
+	}
+}
+
+func GtOrEq(column string) Cmp {
+	return Cmp{
+		op:     geq,
+		column: column,
+		name:   column,
+	}
+}
+
+func GtOrEqNamed(column, name string) Cmp {
+	return Cmp{
+		op:     geq,
+		column: column,
+		name:   name,
+	}
+}
+
+func In(column string) Cmp {
+	return Cmp{
+		op:     in,
+		column: column,
+		name:   column,
+	}
+}
+
+func InNamed(column, name string) Cmp {
+	return Cmp{
+		op:     in,
+		column: column,
+		name:   name,
+	}
+}
+
+func Contains(column string) Cmp {
+	return Cmp{
+		op:     cnt,
+		column: column,
+		name:   column,
+	}
+}
+
+func ContainsNamed(column, name string) Cmp {
+	return Cmp{
+		op:     cnt,
+		column: column,
+		name:   name,
+	}
+}
+
+type cmps []Cmp
+
+func (cs cmps) writeCql(cql *bytes.Buffer) (names []string) {
+	for i, c := range cs {
+		names = append(names, c.writeCql(cql))
+		if i < len(cs)-1 {
+			cql.WriteString(" AND ")
+		}
+	}
+	cql.WriteByte(' ')
+	return
+}