CODEWITHSUNDEEP
autohotkey
john c. j.
john c. j.

Reputation: 1175

Variables, expressions, and `if` statement

I have few similar questions about expressions. I marked them as Q1, Q2 and Q3 for convenience.

First. As stated in the docs,

Variable names in an expression are not enclosed in percent signs (except for pseudo-arrays and other double references). Consequently, literal strings must be enclosed in double quotes to distinguish them from variables.Source

As I understand, this means we should write code like this:

a = aaa
b = zzz

if (a = "aaa" or b = "bbb")
    MsgBox, It works!

However, this seems also works:

a = aaa
b = zzz

if (%a% = aaa or %b% = bbb)
    MsgBox, It works!

Is there some drawbacks in the second way? (Q1)

One possible drawback, which I found myself, is that second method will not work if variable contains only digits. This will not work:

a = 111
b = 999

if (%a% = 111 or %b% = 222)
    MsgBox, It works!

Why it stopped worked now? (Q2)

And also, if variable contains only digits, there seems no need to quote it's value in expression:

a = 111
if (a = "111") ; Also works for a = "aaa"
    MsgBox, It works!

a = 111
if (a = 111)   ; It will not work for a = "aaa". We forced to us quote signs if var contains letters.
    MsgBox, It works too.

Why second way (if (a = 111)) works and should or should not we avoid it? (Q3).

Upvotes: 0

Views: 498

Answers (1)

Relax
Relax

Reputation: 10543

(Q1)

If a variable is enclosed in percent signs within an expression (in your example %a%), whatever that variable contains is assumed to be the name or partial name of another variable.

This also works

a = aaa
b = zzz

if (%a% = a or %h% = cc)
    MsgBox, It works!

because the values of the vars %a% and %h% are not specified.

(Q2)

If both var and value are purely numeric, they will be compared as numbers rather than as strings. Otherwise, they will be compared alphabetically as strings (that is, alphabetical order will determine whether var is greater, equal, or less than value).

(Q3)

Only literal strings must be enclosed in double quotes. If the variable contains only digits, there is no need to quote.

Upvotes: 1

Related Questions