docs: optimize comment and readme

Change-Id: Id8b950d948873fe8d0e4b2b897296c8cf86c5101

Author: andeya

spec_func.go

@@ -29,7 +29,7 @@ var funcList = map[string]func(p *Expr, expr *string) ExprNode{}
 
 // RegFunc registers function expression.
 // NOTE:
-//  example: len($) to returns the v's length;
+//  example: len($), regexp("\\d") or regexp("\\d",$);
 //  If @force=true, allow to cover the existed same @funcName;
 //  The go number types always are float64;
 //  The go string types always are string.

validator/README.md

@@ -8,7 +8,7 @@ A powerful validator that supports struct tag expression.
 - Support for accessing arrays, slices, members of the dictionary
 - Support access to any field in the current structure
 - Support access to nested fields, non-exported fields, etc.
-- Built-in len, sprintf, regexp functions
+- Built-in len, sprintf, regexp, email, phone functions
 - Support simple mode, or specify error message mode
 - Use offset pointers to directly take values, better performance
 

validator/func.go

@@ -7,9 +7,9 @@ import (
 	"github.com/nyaruka/phonenumbers"
 )
 
-// RegValidateFunc registers simple validate function expression.
+// RegValidateFunc registers validate function expression.
 // NOTE:
-//  example: email($) or email();
+//  example: phone($) or phone($,'CN');
 //  If @force=true, allow to cover the existed same @funcName;
 //  The go number types always are float64;
 //  The go string types always are string.