1,847
edits
Octave style guide: Difference between revisions
Jump to navigation
Jump to search
Add Category:Development.
Carandraug (talk | contribs) (→Comments: expand # and ## comment blocks) |
(Add Category:Development.) |
||
| (6 intermediate revisions by 3 users not shown) | |||
| Line 27: | Line 27: | ||
parentheses, like this: | parentheses, like this: | ||
<pre>x = max (sin (y+3), 2);</pre> | <pre>x = max (sin (y + 3), 2);</pre> | ||
An exception are matrix or cell constructors: | An exception are matrix or cell constructors: | ||
| Line 64: | Line 64: | ||
prices = [ 1.01 2.02 3.03 | prices = [ 1.01 2.02 3.03 | ||
44.04 55.05 6.06]; | 44.04 55.05 6.06]; | ||
</pre> | |||
Do include spaces around all binary arithmetic operators, for example | |||
<pre> | |||
x = 1 / (1 + y) ^ 2; | |||
</pre> | |||
An exception is for extremely simple expressions like <pre>n+1</pre>, in | |||
particular when used as an argument to a function or as part of an indexing | |||
expression. For example, you may write | |||
<pre> | |||
x(1:end-1) | |||
</pre> | |||
Another exception is for complex arithmetic expressions. It may improve | |||
readability to omit spaces around higher precedence operators, for example | |||
<pre> | |||
z = cat (dim, (x2.*y3 - x3.*y2), (x3.*y1 - x1.*y3), (x1.*y2 - x2.*y1)); | |||
</pre> | </pre> | ||
| Line 103: | Line 124: | ||
=== Variable names === | === Variable names === | ||
Avoid reusing the names of other functions as local variable names. For | |||
example, try to avoid naming local variables {{codeline|abs}}, | |||
{{codeline|log}}, or {{codeline|pow}}. These functions may be used in a | |||
later change and may lead to confusing errors. | |||
An exception is the use of {{codeline|i}} and {{codeline|j}} as loop indices. | |||
If a function has nothing to do with complex arithmetic, it is common and | |||
acceptable to use {{codeline|i}} and {{codeline|j}} as local variables in | |||
for loops. | |||
== Quoted Strings == | |||
Always use double quotes for strings and characters rather than the Matlab single quote convention. Both quote types are accepted by Octave, but double quoted strings are interpreted slightly differently (see [https://www.gnu.org/software/octave/doc/interpreter/Strings.html Strings] in the manual for details). | |||
'''Do:''' | |||
<pre> | |||
a = "Hello, world"; | |||
b = "x"; | |||
disp ("This \"string\" contains a\nnewline"); | |||
</pre> | |||
'''Don't:''' | |||
<pre> | |||
s = 'Hello, world'; | |||
if (x(1) == 'c') | |||
disp ('Don''t quote one character this way, even if you''re a C programmer'); | |||
endif | |||
</pre> | |||
There are a few edge cases where single quoted strings may be preferable, and are permitted as exceptions under this style guide. | |||
; String containing double quotes | |||
: A string that contains many double quote characters itself, where escaping all of them with backslashes becomes inconvenient, may be easier with single quotes. | |||
; String containing backslashes | |||
: A string that contains literal backslashes, in particular a regular expression pattern, where doubly escaping certain character sequences is both inconvenient and harder to read, is usually better done with single quotes. | |||
; Argument interpreted differently | |||
: A string argument to the regexp family of functions may be interpreted differently depending on whether it is a double quoted or single quoted string. Certain escape sequences are interpreted only in a single quoted string for Matlab compatibility. | |||
== ending blocks == | == ending blocks == | ||
| Line 129: | Line 190: | ||
== ! operator == | == ! operator == | ||
The Octave operator | * The Octave operator <code>!</code> should be used for logical negation, rather than <code>~</code>. | ||
* The negation operator is written with a space between the operator and its target, e.g., <code>! A</code>. | |||
and its target, e.g., | * For comparisons use <code>!=</code> instead of <code>~=</code>. | ||
== Comments == | == Comments == | ||
| Line 188: | Line 248: | ||
The preferred comment mark for places that may need further attention is | The preferred comment mark for places that may need further attention is | ||
with {{codeline|FIXME:}} comments. | with {{codeline|FIXME:}} comments. | ||
[[Category:Development]] | |||