Re: Assembling Complex Strings Containing Carriage Returns Prior to Using Ada.Text_IO.Put?

[NiGHTS <nights@unku.us>]

On Wednesday, October 22, 2014 1:44:30 PM UTC-4, Adam Beneschan wrote:
> On Tuesday, October 21, 2014 10:57:39 PM UTC-7, NiGHTS wrote:
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> > I am converting some code from C to Ada which involves building a complex string containing '\n' characters which would eventually be displayed on the standard output console using the printf() function. 
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> > I tried to copy the same strategy of building the string in Ada like this:
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> > Complex_String : Ada.Strings.Unbounded.Unbounded_String;
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> > EOL            : String := ASCII.CR'Img;
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> As others have pointed out, 'Img is a GNAT-defined attribute; it depends on the Ada-defined attribute 'Image.  'Image is not intended to convert a Character to a one-character String.  If you say
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>     C : Character := 'x';
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>     S : String := Character'Image (C);
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> S will have length 3 and will be "'x'".
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> Character is an enumeration type in Ada, although it's somewhat special.  But the rules for 'Image (and its converse, 'Value) are the same as for other enumeration types: they give you (or expect) a string that looks like what the enumeration value would look like in the enumeration declaration.  For example, with this enumeration type:
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>     type Color is (RED, GREEN, BLUE);
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> the 'Image attribute will produce "RED", "GREEN", or "BLUE".  (It's always upper-case for identifiers.)  And for an enumeration type that has character literals mixed in:
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>     type Whatsit is (This, That, '?');
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> 'Image will produce "THIS", "THAT", or "'?'".  (What makes Character special is that if you give it a non-printable character, there are special rules for what 'Image returns; in your case it returned "CR".)
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>                             -- Adam

This is clear to me now. I will try to avoid 'Img now that I know its GNAT-specific, or at the very least move it to a file specifically named to be compiled only in gnat. Thank you for your help.