Fix precedence of the LIKE operator.

Author: Jan Mercl

doc.go

@@ -673,8 +673,8 @@
 //  Expression = Term { oror Term } .
 //
 //  ExpressionList = Expression { "," Expression } [ "," ].
-//  Factor =  PrimaryFactor  { ( ge | ">" | le | "<" | neq | eq ) PrimaryFactor } [ Predicate ] .
-//  PrimaryFactor = PrimaryTerm  { ( "^" | "|" | "-" | "+" | "LIKE" ) PrimaryTerm } .
+//  Factor =  PrimaryFactor  { ( ge | ">" | le | "<" | neq | eq | "LIKE" ) PrimaryFactor } [ Predicate ] .
+//  PrimaryFactor = PrimaryTerm  { ( "^" | "|" | "-" | "+" ) PrimaryTerm } .
 //  PrimaryTerm = UnaryExpr { ( andnot | "&" | lsh | rsh | "%" | "/" | "*" ) UnaryExpr } .
 //  Term = Factor { andand Factor } .
 //  UnaryExpr = [ "^" | "!" | "-" | "+" ] PrimaryExpression .

expr.go

@@ -182,7 +182,7 @@ func (p *pLike) eval(ctx map[interface{}]interface{}, arg []interface{}) (v inte
 
 		sexpr, ok = expr.(string)
 		if !ok {
-			return nil, fmt.Errorf("non-string expression: %v (value of type %T)", expr, expr)
+			return nil, fmt.Errorf("non-string expression in LIKE: %v (value of type %T)", expr, expr)
 		}
 
 		if p.expr.isStatic() {
@@ -204,7 +204,7 @@ func (p *pLike) eval(ctx map[interface{}]interface{}, arg []interface{}) (v inte
 
 		spattern, ok := pattern.(string)
 		if !ok {
-			return nil, fmt.Errorf("non-string expression: %v (value of type %T)", pattern, pattern)
+			return nil, fmt.Errorf("non-string pattern in LIKE: %v (value of type %T)", pattern, pattern)
 		}
 
 		if re, err = regexp.Compile(spattern); err != nil {