## page was renamed from SamplePage
= I-Beams in Dyalog APL =
<<TableOfContents>>

== Overview ==
This section adds more detail to the I-Beam functionality that has been added to Dyalog APL 12.1.

As ever, please remember the caveat that appears in the Language Guide:

'''Warning''': Although documentation is provided for I-Beam functions, any service provided using I-Beam should be considered as “experimental” and subject to change – without notice - from one release to the next. Any use of I-Beams in applications should therefore be carefully isolated in cover-functions that can be adjusted if necessary.

== 200: Syntax Colouring ==
The Language Reference details the use of 200⌶ with function or operator definitions:

 `200⌶ ⎕NR'foo'`

However, this I-Beam has been extended to include Namespaces, Classes and Interfaces, using the following syntax:

 `200⌶ (⎕src object) type`

where type is one of the following:
||Value ||Object type ||
||1 ||Function (use `⎕nr`) ||
||256 ||Namespace ||
||512 ||Interface ||
||1024 ||Class ||




Since any vector of character vectors could be passed to 200⌶, the type is used to indicate to the interpreter what it should base its analysis on.  So, for example if you run

 `200⌶(⎕src mynamespace) 1`

then the namespace-specific tags will appear as 243 - "Mismatched control structure"; you can't have a :Namespace in a function definition !

Whereas if you run

 `200⌶(⎕src mynamespace) 256`

then the `:Namespace` element will appear as a valid one (177).

The attached file lists all of the  [[attachment:121_ibeam200.txt|syntactic colour elements]].  Note that this list is very version-specific; this list was generated on 2009-11-20 for V12.1, and may be extended, reduced or removed altogether in future versions.
----
CategoryArticles CategoryArticlesDyalog