FPC 3.2.2 - maximum Length of Identifiers ?

[paule32]

Hello,
what is the maximum Length of a Identifier like:

TClass_myForm_1_myForm_2_myForm_A_mnyForm_A_1_ = class(TForm) ... end;

?

[Fibonacci]

Code: Pascal  [Select][+][-]

1. project1.lpr(5,3) Error: Constant strings cannot be longer than 255 chars

[paule32]

Hi fibonacci,

Thanks for reply - but this are no good news for me.
I working on a Compiler that supports nested classes.
Currently it converts from one DSL to FPC.

Are Hashes allowed for Class Names ?

like:  T12abc000111_aaa312
???

this will be going into funny way - I see it come ...

[Fibonacci]

You can create shorter named classes and a map with longer names. Im not sure what exactly do you want to achieve

Code: Pascal  [Select][+][-]

1. type
2.   short_name_for_class = class
3.     procedure testproc;
4.   end;
5.  
6.   classmapentry = record
7.     name: string;
8.     c: tclass;
9.   end;
10.  
11. const
12.   classes: array[0..0] of classmapentry = (
13.     (name: 'long_name_for_class_long_name_for_class_long_name_for_class_long_name_for_class'; c: short_name_for_class)
14.   );
15.  
16. procedure short_name_for_class.testproc;
17. begin
18.   writeln('testproc called');
19. end;
20.  
21. function getclass(classname: string; out c: tclass): boolean;
22. var
23.   i: integer;
24. begin
25.   result := false;
26.   for i := 0 to high(classes) do
27.     if classes[i].name = classname then begin
28.       c := classes[i].c;
29.       exit(true);
30.     end;
31. end;
32.  
33. var
34.   myclass: tclass;
35.  
36. begin
37.   if getclass('long_name_for_class_long_name_for_class_long_name_for_class_long_name_for_class', myclass) then begin
38.     short_name_for_class(myclass).testproc;
39.   end;
40.  
41.   readln;
42. end.

AFAIK, RTTI in FPC is not at the level you could find a class by its string representation. If it were you could in fact keep the name of the classes as hashes and find them by hashing a string with the class name. But for now, you can use something like above.

[paule32]

Thanks fibo.

Currently I work in Hybride Way:
DSL (Source Code) => C++ (Compiler EXE) => FPC (Source Code) => EXE (Compiled x86_64)

[PascalDragon]

Are Hashes allowed for Class Names ?

like:  T12abc000111_aaa312
???

As long as an identifier starts with a letter from A-Z (upper- or lowercase) or an underscore and further contains either these or numbers it's a valid Pascal identifier.

[paule32]

starting with this Code:

Code: Text  [Select][+][-]

1. parameter bModal
2.  
3. class myForm_1 of Form
4.  
5.     class myForm_2 of Form
6.    
7.         class myForm_A of Form
8.        
9.             class mnyForm_A_1 of Form
10.             classend
11.            
12.         classend
13.        
14.         class myForm_B of Form
15.         classend
16.        
17.         class myForm_C of Form
18.        
19.             class myForm_C2 of Form
20.             classend
21.         classend
22.     classend
23.    
24.     class myForm_2B of Form
25.     classend
26. classend
27.  

I get this followed Code below.
This will then result into a 200 KBytes .ppu File
This will then result into a 100 KBytes .o     File

Code: Pascal  [Select][+][-]

1. {$mode delphi}
2. UNIT test;
3.  
4. INTERFACE
5.  
6. USES
7.   Interfaces, SysUtils, Classes, Forms, Dialogs;
8.  
9. TYPE
10.   TParamScope = (
11.     PS_UNKNOWN   = 0,
12.     PS_LOCAL     = 1,
13.     PS_GLOBAL    = 2,
14.     PS_PRIVATE   = 3,
15.     PS_PROTECTED = 4
16.   );
17.   TParamType = (
18.     PT_UNKNOWN = 0,
19.     PT_NUMERIC = 1,
20.     PT_STRING  = 2,
21.     PT_OBJECT  = 3  );
22.  
23. TYPE
24.   TDBParameterClass = CLASS(TObject)
25.   public
26.     pName  : String      ;
27.     pScope : TParamScope ;
28.     pType  : TParamType  ;
29.     pSize  : Integer     ;
30.     pData  : PChar       ;
31.   END;
32.  
33. TYPE
34.   TDBClass_06200f92_7181_4db7_8e79_9d5cee2d6891 = CLASS(TForm)
35.   PRIVATE
36.     FParameter: ARRAY [0..1] OF TDBParameterClass;
37.   PUBLIC
38.     PROCEDURE Init;
39.     PROCEDURE DeInit;
40.   END;
41.  
42. TYPE
43.   TDBClass_57b5bbea_4f3e_40f3_9c06_59204ddaa18f = CLASS(TForm)
44.   PRIVATE
45.     FParameter: ARRAY [0..1] OF TDBParameterClass;
46.   PUBLIC
47.     PROCEDURE Init;
48.     PROCEDURE DeInit;
49.   END;
50.  
51. TYPE
52.   TDBClass_6e546657_cf75_402f_a9a7_2a2df502d1fe = CLASS(TForm)
53.   PRIVATE
54.     FParameter: ARRAY [0..1] OF TDBParameterClass;
55.   PUBLIC
56.     PROCEDURE Init;
57.     PROCEDURE DeInit;
58.   END;
59.  
60. TYPE
61.   TDBClass_b100651b_44eb_475c_a0fc_c6700b95d0ce = CLASS(TForm)
62.   PRIVATE
63.     FParameter: ARRAY [0..1] OF TDBParameterClass;
64.   PUBLIC
65.     PROCEDURE Init;
66.     PROCEDURE DeInit;
67.   END;
68.  
69. TYPE
70.   TDBClass_b8f06298_ed28_4a53_80df_f6d31d626022 = CLASS(TForm)
71.   PRIVATE
72.     FParameter: ARRAY [0..1] OF TDBParameterClass;
73.   PUBLIC
74.     PROCEDURE Init;
75.     PROCEDURE DeInit;
76.   END;
77.  
78. TYPE
79.   TDBClass_df4d5daf_d635_4550_97e6_f7b474cb3f7a = CLASS(TForm)
80.   PRIVATE
81.     FParameter: ARRAY [0..1] OF TDBParameterClass;
82.   PUBLIC
83.     PROCEDURE Init;
84.     PROCEDURE DeInit;
85.   END;
86.  
87. TYPE
88.   TDBClass_e464d03c_8324_4b1a_a01a_f4ffeba5388c = CLASS(TForm)
89.   PRIVATE
90.     FParameter: ARRAY [0..1] OF TDBParameterClass;
91.   PUBLIC
92.     PROCEDURE Init;
93.     PROCEDURE DeInit;
94.   END;
95.  
96. TYPE
97.   TDBClass_f74fe285_c96d_4948_b31f_e35524b55630 = CLASS(TForm)
98.   PRIVATE
99.     FParameter: ARRAY [0..1] OF TDBParameterClass;
100.   PUBLIC
101.     PROCEDURE Init;
102.     PROCEDURE DeInit;
103.   END;
104.  
105.  
106. IMPLEMENTATION
107.  
108. PROCEDURE TDBClass_06200f92_7181_4db7_8e79_9d5cee2d6891.Init;
109. BEGIN
110.   FParameter[0] := TDBParameterClass.Create;
111.   FParameter[0].pName  := 'bModal';
112.   FParameter[0].pScope := TParamScope(PS_GLOBAL);
113.   FParameter[0].pType  := TParamType(PT_UNKNOWN);
114. END;
115.  
116. PROCEDURE TDBClass_06200f92_7181_4db7_8e79_9d5cee2d6891.DeInit;
117. VAR
118.   IDX : Integer;
119. BEGIN
120.   FOR IDX := HIGH(FParameter) DOWNTO LOW(FParameter) DO
121.   BEGIN
122.     FParameter[IDX].Free;
123.     FParameter[IDX] := NIL;
124.   END;
125. END;
126.  
127. PROCEDURE TDBClass_57b5bbea_4f3e_40f3_9c06_59204ddaa18f.Init;
128. BEGIN
129.   FParameter[0] := TDBParameterClass.Create;
130.   FParameter[0].pName  := 'bModal';
131.   FParameter[0].pScope := TParamScope(PS_GLOBAL);
132.   FParameter[0].pType  := TParamType(PT_UNKNOWN);
133. END;
134.  
135. PROCEDURE TDBClass_57b5bbea_4f3e_40f3_9c06_59204ddaa18f.DeInit;
136. VAR
137.   IDX : Integer;
138. BEGIN
139.   FOR IDX := HIGH(FParameter) DOWNTO LOW(FParameter) DO
140.   BEGIN
141.     FParameter[IDX].Free;
142.     FParameter[IDX] := NIL;
143.   END;
144. END;
145.  
146. PROCEDURE TDBClass_6e546657_cf75_402f_a9a7_2a2df502d1fe.Init;
147. BEGIN
148.   FParameter[0] := TDBParameterClass.Create;
149.   FParameter[0].pName  := 'bModal';
150.   FParameter[0].pScope := TParamScope(PS_GLOBAL);
151.   FParameter[0].pType  := TParamType(PT_UNKNOWN);
152. END;
153.  
154. PROCEDURE TDBClass_6e546657_cf75_402f_a9a7_2a2df502d1fe.DeInit;
155. VAR
156.   IDX : Integer;
157. BEGIN
158.   FOR IDX := HIGH(FParameter) DOWNTO LOW(FParameter) DO
159.   BEGIN
160.     FParameter[IDX].Free;
161.     FParameter[IDX] := NIL;
162.   END;
163. END;
164.  
165. PROCEDURE TDBClass_b100651b_44eb_475c_a0fc_c6700b95d0ce.Init;
166. BEGIN
167.   FParameter[0] := TDBParameterClass.Create;
168.   FParameter[0].pName  := 'bModal';
169.   FParameter[0].pScope := TParamScope(PS_GLOBAL);
170.   FParameter[0].pType  := TParamType(PT_UNKNOWN);
171. END;
172.  
173. PROCEDURE TDBClass_b100651b_44eb_475c_a0fc_c6700b95d0ce.DeInit;
174. VAR
175.   IDX : Integer;
176. BEGIN
177.   FOR IDX := HIGH(FParameter) DOWNTO LOW(FParameter) DO
178.   BEGIN
179.     FParameter[IDX].Free;
180.     FParameter[IDX] := NIL;
181.   END;
182. END;
183.  
184. PROCEDURE TDBClass_b8f06298_ed28_4a53_80df_f6d31d626022.Init;
185. BEGIN
186.   FParameter[0] := TDBParameterClass.Create;
187.   FParameter[0].pName  := 'bModal';
188.   FParameter[0].pScope := TParamScope(PS_GLOBAL);
189.   FParameter[0].pType  := TParamType(PT_UNKNOWN);
190. END;
191.  
192. PROCEDURE TDBClass_b8f06298_ed28_4a53_80df_f6d31d626022.DeInit;
193. VAR
194.   IDX : Integer;
195. BEGIN
196.   FOR IDX := HIGH(FParameter) DOWNTO LOW(FParameter) DO
197.   BEGIN
198.     FParameter[IDX].Free;
199.     FParameter[IDX] := NIL;
200.   END;
201. END;
202.  
203. PROCEDURE TDBClass_df4d5daf_d635_4550_97e6_f7b474cb3f7a.Init;
204. BEGIN
205.   FParameter[0] := TDBParameterClass.Create;
206.   FParameter[0].pName  := 'bModal';
207.   FParameter[0].pScope := TParamScope(PS_GLOBAL);
208.   FParameter[0].pType  := TParamType(PT_UNKNOWN);
209. END;
210.  
211. PROCEDURE TDBClass_df4d5daf_d635_4550_97e6_f7b474cb3f7a.DeInit;
212. VAR
213.   IDX : Integer;
214. BEGIN
215.   FOR IDX := HIGH(FParameter) DOWNTO LOW(FParameter) DO
216.   BEGIN
217.     FParameter[IDX].Free;
218.     FParameter[IDX] := NIL;
219.   END;
220. END;
221.  
222. PROCEDURE TDBClass_e464d03c_8324_4b1a_a01a_f4ffeba5388c.Init;
223. BEGIN
224.   FParameter[0] := TDBParameterClass.Create;
225.   FParameter[0].pName  := 'bModal';
226.   FParameter[0].pScope := TParamScope(PS_GLOBAL);
227.   FParameter[0].pType  := TParamType(PT_UNKNOWN);
228. END;
229.  
230. PROCEDURE TDBClass_e464d03c_8324_4b1a_a01a_f4ffeba5388c.DeInit;
231. VAR
232.   IDX : Integer;
233. BEGIN
234.   FOR IDX := HIGH(FParameter) DOWNTO LOW(FParameter) DO
235.   BEGIN
236.     FParameter[IDX].Free;
237.     FParameter[IDX] := NIL;
238.   END;
239. END;
240.  
241. PROCEDURE TDBClass_f74fe285_c96d_4948_b31f_e35524b55630.Init;
242. BEGIN
243.   FParameter[0] := TDBParameterClass.Create;
244.   FParameter[0].pName  := 'bModal';
245.   FParameter[0].pScope := TParamScope(PS_GLOBAL);
246.   FParameter[0].pType  := TParamType(PT_UNKNOWN);
247. END;
248.  
249. PROCEDURE TDBClass_f74fe285_c96d_4948_b31f_e35524b55630.DeInit;
250. VAR
251.   IDX : Integer;
252. BEGIN
253.   FOR IDX := HIGH(FParameter) DOWNTO LOW(FParameter) DO
254.   BEGIN
255.     FParameter[IDX].Free;
256.     FParameter[IDX] := NIL;
257.   END;
258. END;
259.  
260. END.

This is not optimized. yet

[Ozz_Nixon]

Hello,
what is the maximum Length of a Identifier like:

TClass_myForm_1_myForm_2_myForm_A_mnyForm_A_1_ = class(TForm) ... end;

?

Free Pascal supports up to 127 characters for an Identifier.
C99 = 32 characters.
TP7 = 63 characters.
DCC32 = E2056 String literals may have at most 255.


Ozz 

[marcov]

Note that the backend of linkers might have other limits.

[440bx]

Note that the backend of linkers might have other limits.

Good point.
It's easy to forget/overlook that there are often other "parts" involved in the creation of an executable that may have different limits.

Also, as long as those other parts don't need to refer to items that exceed their limit(s), there is no harm done but, it is not always obvious when a limit that has been exceeded in other parts will play a role.

In those cases, it's always a good idea to write a few test cases to determine the behavior of all the parts involved.

[paule32]

indeed, test cases are good ideas.

currently I don't know how big can .ppu or .o Files be.
When I look into the binary File I see a lot of Numbers from the Header Informations (also the .o bject File).

I check it out: these Numbers are Files which results into the Format of: number.o
The created .a rchive File contains this Files, too.

So far I lay not wrong: Linux open File Limit can be increase but I thinking it is on 32.000 Files by default.
On Windows - I don't know.

Very very much System knowledge to know...

[440bx]

Many limits are imposed by the data types used internally.

For instance, in a PE file, there are fields interpreted as 32 bit signed integers.  that pretty much forces a PE file to be a maximum of 2GB because if it's allowed to be larger than that, there will be offsets that don't fit in a signed 32 bit.

Another thing that is a source of problems is the O/S bitness.  for instance, in the 32bit version of Windows, the affinity bitmask is 32 bits (a DWORD) which causes a problem when there are more than 32 cores.  In 64 bit the affinity is 64 bits which is already at the edge for a PC (processors with 64 cores are fairly common already.)  that's why there are "processor groups" which removes some of those limits.

There are plenty of limits I am not aware of but, I do know that Windows 7 falls all over itself when the number of processes exceeds roughly 2500, I don't know the exact number and I don't know exactly the reason(s) why either but, I do know it cannot gracefully handle that many processes.

Same thing with file size.  Theoretically, the maximum file size is 16TB but, in reality it seems to be about 16TB - 1MB and, that's a bit "rough" because some have reported that once created, deleting it seems to be problematic (I cannot be precise because I have not personally tried it.)

Anyways... it's always fun to push the envelop.  That shows how robust and resilient a piece of software is.