From 2d8a5c066b5df7ca23b2b820203142faade68a4e Mon Sep 17 00:00:00 2001
From: Steve Pritchard <public.pritchard@gmail.com>
Date: Sat, 15 Aug 2020 17:19:19 -0400
Subject: [PATCH] Update README.md

This describes the proposed enhancement to mustache.js that allows for what I call instream parameters.

The full use of this can be seen in the project at http://gael-home.appspot.com/home/samcas/samcas-implementation.htm for which the code is at https://github.com/srp7474/samcas
---
 README.md | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/README.md b/README.md
index 5c25dd4..dca472d 100644
--- a/README.md
+++ b/README.md
@@ -300,6 +300,27 @@ Output:
 * Ringo Starr
 ```
 
+#### Instream Parameters
+
+This is a proposal by Steve Pritchard implemented in the modified mustache.js in this fork. It is less than 2 dozen lines of code but made a significant simplification to the code generator that was implmented using Mustache.js. In brief the {{funcName(parm1,parm2)}} is scanned for an opening and closing parenthesis.  If found the parenthetical string parm is parsed by splitting on the ',' character and the array is passed to the function (*funcName* in this case). *funcName* processes the parameters and returns a string in the normal fashion. (To allow for alternate parsing, the modification uses an `*` right after the opening paren as an escape mechanism so the unsplit string is passed as a single parameter to the receiving function).
+
+I was thus able to write an *isState* function that would generate something only when the context state matched the parmameter state.
+
+```html
+{{#isState(ready)}}
+<p>only generated when internal context state matches 'ready'</p>
+{{/isState(ready)}}
+```
+
+The other major use was to generate HTML based on the template context and the supplied parameters. Thus
+
+```html
+{{&elem(text,fldName,label=Input Name,onChange=changeFunc)}}
+```
+could generate HTML connected into an internal model that was the context of the template.
+
+I also employ a convention of a leading `*` with each parameter as a trigger for the receiving function to do a contextual lookup and thus provide a dynamic replacement value;
+
 #### Functions
 
 If the value of a section key is a function, it is called with the section's literal block of text, un-rendered, as its first argument. The second argument is a special rendering function that uses the current view as its view argument. It is called in the context of the current view object.