Basic Coding Style

This Lesson is estimated to be completed in 5 minutes.

You should have first completed the Lesson: Basic Commands.

Description

As in any other programming language, there are certain coding style rules that are part of the culture of programming in M. These rules, or rather Guidelines sometimes become part of the culture of a given project. Programmers would typically develop preferences to one style or another. It is important however to respect the style adopted by the project that you are working on.

Uppercase versus Lowercase

It has been traditional to write M using uppercase letters as in

SET SUM=0
SET NAME="Linus Torvalds"
SET YEAR=1984
WRITE NAME
WRITE YEAR
WRITE SUM

but the same can be written using lowercase letters as in

set sum=0
set name="Linus Torvalds"
set year=1984
write name
write year
write sum

Note however that lowercase variable names are differentiated from uppercase variable name. That is, they become two different variables.

In other words, in M language, commands are not case sensitive, while variable names are case sensitive.

set sum=0
set SUM=7
write sum," : ",SUM

produces the output

0 : 7

The Short Form

Commands in M can be shortened to the first unambiguouos letters of the command name.

For example:

SET NAME="Elvis"
WRITE NAME

can be shortened to

S NAME="Elvis"
W NAME

As a good practice of writing readable and maintainable code you should strive for writing the long form of the commands. However, it will be common for you to run into code that uses the short form, and therefore, this section is only intended to help you read such code, not as a recommendation of writing using the short form.

Historically, there used to be memory-saving reasons for using the short form. This is no longer the case with modern hardware.

The Horizontal Form

Several M commands can be placed in the same line, separating them by spaces

For example

S NAME="Elvis" W NAME

This is called the horizontal form, in contrast to the Vertical form

S NAME="Elvis"
W NAME

As a good practice of writing readable and maintainable code you should strive for writing the vertical form of the commands. However, it will be common for you to run into code that uses the horizontal form, and therefore, this section is only intended to help you read such code, not as a recommendation of writing using the horizontal form.

Next Lesson: Basic Code Life Cycle.