parser: Add support for mathmatical operators

internal/dinosql/parser.go

@@ -379,6 +379,7 @@ func parseQuery(c core.Catalog, stmt nodes.Node, source string) (*Query, error)
 default:
 return nil, nil
 }
+
 rawSQL, err := pluckQuery(source, raw)
 if err != nil {
 return nil, err
@@ -562,9 +563,15 @@ func outputColumns(c core.Catalog, node nodes.Node) ([]core.Column, error) {
 if res.Name != nil {
 name = *res.Name
 }
-if postgres.IsComparisonOperator(join(n.Name, "")) {
+switch {
+case postgres.IsComparisonOperator(join(n.Name, "")):
 // TODO: Generate a name for these operations
 cols = append(cols, core.Column{Name: name, DataType: "bool", NotNull: true})
+case postgres.IsMathematicalOperator(join(n.Name, "")):
+// TODO: Generate correct numeric type
+cols = append(cols, core.Column{Name: name, DataType: "pg_catalog.int4", NotNull: true})
+default:
+cols = append(cols, core.Column{Name: name, DataType: "any", NotNull: false})
 }
 
 case nodes.CoalesceExpr:

internal/dinosql/query_test.go

@@ -690,6 +690,19 @@ func TestQueries(t *testing.T) {
 },
 },
 },
+{
+"mathmatical-operator",
+`
+CREATE TABLE foo (num integer not null);
+SELECT *, num / 1024 as division FROM foo;
+`,
+Query{
+Columns: []core.Column{
+{Name: "num", DataType: "pg_catalog.int4", NotNull: true, Table: public("foo")},
+{Name: "division", DataType: "pg_catalog.int4", NotNull: true},
+},
+},
+},
 } {
 test := tc
 t.Run(test.name, func(t *testing.T) {

internal/postgres/types.go

@@ -14,3 +14,28 @@ func IsComparisonOperator(s string) bool {
 }
 return true
 }
+
+func IsMathematicalOperator(s string) bool {
+switch s {
+case "+":
+case "-":
+case "*":
+case "/":
+case "%":
+case "^":
+case "|/":
+case "||/":
+case "!":
+case "!!":
+case "@":
+case "&":
+case "|":
+case "#":
+case "~":
+case "<<":
+case ">>":
+default:
+return false
+}
+return true
+}