Revision as of 11:40, 15 May 2012 by Scimonster (talk | contribs) (Procedures in Scratch: Removed quote.)

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Procedures, also called functions or methods, are a tool in many programming languages, which allow common blocks of code to be grouped and called by a single name. Blocks in Scratch are procedures themselves, as they are blocks of compiled code executed all at once. Procedures have inputs or arguments, which are used to edit the procedure's effect slightly. For example, the "move (10) steps" block has the numerical argument (the bracketed bit) which specifies the distance to be moved: 10 pixels in this case.

Procedures in Scratch

A "jump" procedure.
A "jump" procedure with an argument.

Procedures will be added in Scratch 2.0.[1] There will be a "My Blocks" section, where procedures in the project are stored.[2] The procedures will be local to each sprite.[3] Procedures in Scratch 2.0 will only be Stack Blocks, not Reporter or Boolean block styles. It remains to see whether they will be recursive or not. Procedures are expected to take arguments. Reporter or boolean procedures will not be available in Scratch 2.0, but may be in future versions.[4]

Procedures in BYOB/Snap!

Snap!, previously called BYOB (Build Your Own Blocks), is a Scratch modification that allows procedures. Snap!'s procedures allow all 3 types of blocks, with arguments, and also recursion.

Procedures in Squeak

Main article: Squeak Tutorial#Methods

Procedures in Squeak are called methods.

References

  1. http://blog.scratch.mit.edu/2011/03/scratch-20-progress-report-create-your.html
  2. http://blog.scratch.mit.edu/2012/02/scratch-20-project-page-and-project.html
  3. http://scratch.mit.edu/forums/viewtopic.php?pid=719181#p719181
  4. http://scratched.media.mit.edu/discussions/scratch-20/custom-block-types