Repository: struts-site Updated Branches: refs/heads/master 46a2618ca -> 27a47e7f8
Adds missing Alt Syntax page Project: http://git-wip-us.apache.org/repos/asf/struts-site/repo Commit: http://git-wip-us.apache.org/repos/asf/struts-site/commit/27a47e7f Tree: http://git-wip-us.apache.org/repos/asf/struts-site/tree/27a47e7f Diff: http://git-wip-us.apache.org/repos/asf/struts-site/diff/27a47e7f Branch: refs/heads/master Commit: 27a47e7f8b4ee49327d98587468c003b887561c8 Parents: 46a2618 Author: Lukasz Lenart <lukaszlen...@apache.org> Authored: Thu Sep 21 12:12:40 2017 +0200 Committer: Lukasz Lenart <lukaszlen...@apache.org> Committed: Thu Sep 21 12:12:40 2017 +0200 ---------------------------------------------------------------------- source/tag-developers/alt-syntax.md | 57 ++++++++++++++++++++++++++++++++ source/tag-developers/index.md | 2 +- 2 files changed, 58 insertions(+), 1 deletion(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/struts-site/blob/27a47e7f/source/tag-developers/alt-syntax.md ---------------------------------------------------------------------- diff --git a/source/tag-developers/alt-syntax.md b/source/tag-developers/alt-syntax.md new file mode 100644 index 0000000..db41f97 --- /dev/null +++ b/source/tag-developers/alt-syntax.md @@ -0,0 +1,57 @@ +--- +layout: default +title: Tag Developers Guide (WIP) +--- + +# Alt Syntax + +The _altSyntax_ is an option that can be defined in `struts.xml`. By default it is set to true and it is **strongly** +recommend you do not change that unless you are upgrading from WebWork 2.1.7 or previous versions. + +> You can also turn on the altSyntax on a per-page basis by using the _set_ tag. Simply set the name _useAltSyntax_ +> to the value _true_ . From this point on, all tags will use the altSyntax for the rest of the request. + +The altSyntax changes the behavior of how tags are interpreted. Instead of evaluating each tag parameter against +the value stack and needing single quotes to mark string literals, only marked expressions are evaluated. + +Example: + +the following code uses the [Tag Syntax](tag-syntax.html): + +```jsp +<s:iterator value="cart.items"> + ... + <s:textfield label="'Cart item No.' + #rowstatus.index + ' note'" + name="'cart.items[' + #rowstatus.index + '].note'" + value="note" /> +</s:iterator> +``` + +this is somewhat counter intuitive to normal HTML tag behaviour, and you get loads of single quotes. Now the same example +in altSyntax: + +```jsp +<s:iterator value="cart.items"> + ... + <s:textfield label="Cart item No. %{#rowstatus.index} note" + name="cart.items[%{#rowstatus.index}].note" + value="%{note}" /> +</s:iterator> +``` + +Only expressions enclosed with `%{}` are evaluated. The code is shorter and clearer, very similar to JSTL EL usage. +Quoting problems, eg. with javascript function calls, are avoided. + +In order to fully understand why this option exists and what the differences are, it is best to get a bit of history +about WebWork. + +> If you are _not_ upgrading from WebWork 2.1.7 or previous versions and you don't care about the history of WebWork's +> evolution, you can skip this section. See the [Tag Syntax](tag-syntax.html) section for more information +> on the standard tag syntax support + + +## History + +In WebWork 2.1.4, the altSyntax option was introduced. The book, WebWork in Action, while based around WebWork 2.1.7, +was entirely written with the assumption that the altSyntax was enabled. As of WebWork 2.2, the altSyntax is turned +on by default and eventually the old syntax will no longer be supported and will be removed from the code. http://git-wip-us.apache.org/repos/asf/struts-site/blob/27a47e7f/source/tag-developers/index.md ---------------------------------------------------------------------- diff --git a/source/tag-developers/index.md b/source/tag-developers/index.md index b9c7efc..f352dbb 100644 --- a/source/tag-developers/index.md +++ b/source/tag-developers/index.md @@ -18,7 +18,7 @@ The framework offers a flexible view layer that supports multiple view technolog - [OGNL Basics](ognl-basics.html) - [OGNL Expression compilatio](ognl-expression-compilation.html) - [Tag Syntax](tag-syntax.html) -- _Alt Syntax_ +- [Alt Syntax](alt-syntax.html) - [JSP](jsp.html) + [specific tags](jsp-tags.html) + [FreeMarker](freemarker.html)
