CODEWITHSUNDEEP
inno-setupdirectivepreprocessor
JConstantine
JConstantine

Reputation: 1070

What is the point of the #emit directive in Inno Setup?

Here are examples from the #emit directive documentation:

[Files]
#emit 'Source: "file1.ext"; DestDir: {' + MyDestDir + '}'
Source: "file2.ext"; DestDir: {#MyDestDir}
#emit GenerateVisualCppFilesEntries ; user defined function

In the first line I don't understand the DestDir part. Looks like the # symbol is missing there.

I understand the second line. But why do we need to use the #emit directive like in line 1 anyway?

Upvotes: 2

Views: 355

Answers (1)

Martin Prikryl
Martin Prikryl

Reputation: 202534

Inno Setup preprocessor directives can be invoked using two syntaxes.

A basic syntax:

#directive params

And an inline syntax:

{#directive params}

On top of that, the #emit directive is the default inline directive, assumed, when no explicit directive name is specified.

So these three are equivalent:

#emit MyDestDir

{#emit MyDestDir}

{#MyDestDir}

Though the first does not make sense with a path variable, as it would result in invalid script syntax – but it can be used with a variable that contains a valid script syntax:

#define FileSectionEntry 'Source: ' + MySource + '; DestDir: ' + MyDestDir
#emit FileSectionEntry

While the other two inline examples can make sense, but only with other code on the same line, like in the code from your question:

Source: "file2.ext"; DestDir: {#MyDestDir}

Additionally an #emit with a (string) constant is basically pointless, as you can achieve the same without preprocessor.

These three are equivalent:

Source: "file2.ext"; DestDir: "{app}"

#emit 'Source: "file2.ext"; DestDir: "{app}"'

{#'Source: "file2.ext"; DestDir: "{app}"'}

So getting back to the code in your script, these are (almost) equivalent:

#emit 'Source: "file1.ext"; DestDir: {' + MyDestDir + '}'

Source: "file1.ext"; DestDir: {#MyDestDir}

The only problem is that I believe the curly brackets in the first line should not be there. The line should be:

#emit 'Source: "file1.ext"; DestDir: ' + MyDestDir

I have submitted a fix for this. It's basically another copy of the typo from your previous question: Why is there an additional pair of curly braces on the Inno Setup Preprocessor:#emit page?

Upvotes: 2

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