"strings"
	"time"
)

// FuncName - SQL function name.
type FuncName string

// SQL Function name constants
const (
	// Conditionals
	sqlFnCoalesce FuncName = "COALESCE"
	sqlFnNullIf   FuncName = "NULLIF"

	// Conversion
	sqlFnCast FuncName = "CAST"

	// Date and time
	sqlFnDateAdd     FuncName = "DATE_ADD"
	sqlFnDateDiff    FuncName = "DATE_DIFF"
	sqlFnExtract     FuncName = "EXTRACT"

	aggregate *aggVal
}

// SimpleArgFunc represents functions with simple expression
// arguments.
type SimpleArgFunc struct {
	FunctionName string `parser:" @(\"AVG\" | \"MAX\" | \"MIN\" | \"SUM\" |  \"COALESCE\" | \"NULLIF\" | \"TO_STRING\" | \"TO_TIMESTAMP\" | \"UTCNOW\" | \"CHAR_LENGTH\" | \"CHARACTER_LENGTH\" | \"LOWER\" | \"UPPER\") "`

	ArgsList []*Expression `parser:"\"(\" (@@ (\",\" @@)*)?\")\""`
}