home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Libris Britannia 4
/
science library(b).zip
/
science library(b)
/
PROGRAMM
/
PASCAL
/
0826.ZIP
/
TREF2D.ARC
/
T-REFCH2.DOC
< prev
next >
Wrap
Text File
|
1987-09-20
|
13KB
|
331 lines
Chapter II - The Source Lister
This chapter deals primarily with the Source Listing program: how to
print the information you want and how to interpret the listing. The Source
Listing program is activated by positioning the cursor over the 'Source
Listing' field, and striking the space bar until the word "ON" appears within
the cursor. To deactivate the source lister, hit the space bar again and the
word "OFF" will appear. The nine fields that appear on the screen below the
'Source Listing' field relate to specific information to be included or not
included in the source listing. They are all updated in the same manner as
the 'Source Listing' field: by placing the block cursor over the field and
striking the space bar until the desired value appears within the cursor
block. The fields are as follows:
The 'Reserve Words' field is used to tell the program how the reserve
words are to be formatted to the output. You can specify one of four
different formats: "UPPER" capitalizes all letters, "LOWER" prints all letters
in lower-case, "FORML" follows formal naming conventions, and "AS IS" prints
the letters as they are read. The following are examples of different reserve
words and how the output would be formatted; the first column is how the
reserve word would be hypothetically read from the input file:
Input UPPER LOWER FORML AS IS
----- ----- ----- ----- -----
begin BEGIN begin Begin begin
FOR FOR for For FOR
wITH WITH with With wITH
Array ARRAY array Array Array
The 'Identifiers' field's function is similar to the 'Reserve Words'
field described above: it formats the style of lettering for all identifiers
to that requested. The same four formatting styles listed above are available
for this field. However, here we must describe a feature of the "FORML"
format not mentioned above. Since most Pascal compilers allow the use of the
underline symbol (_) within an identifier (to make the source code more read-
able), the "FORML" style makes use of this: not only is the first letter in
the identifier capitalized, but each letter following the underline symbol is
also capitalized. Therefore, 'hot_item' becomes 'Hot_Item', 'not_so_fast'
becomes 'Not_So_Fast', and 'ab_ra_ca_da_bra' becomes 'Ab_Ra_Ca_Da_Bra'.
The purpose of having four formats is to provide a large variety of
choices. Even given these variations, you will most likely select and use one
format for reserve words (i.e., "UPPER") and another format for identifiers
(i.e., "FORML") that best suits your specific purposes.
The 'Line Numbers' field activates ("ON") or deactivates ("OFF") the
printing of source line numbers to the left of each line of output. If
activated, each source line on the output will have a line number printed
ahead of it. There are two formats the line numbers may appear in, depending
on whether the 'Include Files' field is activated during the listing (see
page 10 for a description of this field).
If the 'Include Files' field is activated, the line numbers will appear
in two columns: the line number of the main input file and the line number of
the include file. The line number of the main input file is incremented for
each line read from the 'Active Input File' as specified at the top of the
screen. When an include file compiler directive, such as '{$i extra.prc}', is
6
scanned from the main input file, the program will begin printing the include
file source code starting immediately after printing the line in which the
include file compiler directive is on. At this point (until the end of the
include file is reached), the line number of the main input file will remain
the same and the line number of the include file will begin (starting from 1)
incrementing. The line number of the include file, when the program is
reading from the main input file, is not printed. For example, the following
shows how, when the compiler directive '{$I this.prc}' is scanned, the file
'THIS.PRC' is sent directly to the output.
1 PROGRAM Sample;
2 VAR I:Integer;
3
4 {$I This.Prc}
4 1 PROCEDURE This;
4 2 BEGIN
4 3 Write('This is just a sample.');
4 4 END;
5
6 BEGIN
7 FOR I:=1 to 10 DO This;
8 Writeln;
9 END.
The use of separate line numbers on the listing becomes evident when you
bring either the main file or any of the include files up under the Turbo
editor. Since the Turbo editor prints the cursor's location on the top line
of the screen, the line number you are searching for is the same line number
on the listing. If the 'Include Files' field is not activated (e.g., "No"),
only the line number of the main input file is printed. For example, if the
above main file were printed without the include file activated (set to "No"),
it would look like:
1 PROGRAM Sample;
2 VAR I:Integer;
3
4 {$I This.Prc}
5
6 BEGIN
7 FOR I:=1 to 10 DO This;
8 Writeln;
9 END.
The 'Lexical Levels' field, when activated ("ON"), will print for each
source line a value representing the lexical, or procedural, depth of the
program. Therefore, as the program scans the beginning of a procedure or
function, the lexical level of the program is incremented; the level is decre-
mented when the procedure or function is exited.
7
1 PROGRAM Sample;
1 VAR I:Integer;
1
2 PROCEDURE This;
2
3 PROCEDURE Now_That;
3 BEGIN
3 Writeln;
3 END;
2
2 BEGIN
2 Write('This is just a sample.');
2 Now_That;
2 END;
1
1 BEGIN
1 FOR I:=1 to 10 DO This;
1 END.
The 'Block Levels' field, when activated ("ON"), will print a value
representing the structured statement depth within the procedure or function
being scanned. The value is printed on each line of the output. Whenever a
structured statement (e.g., the IF, the FOR, the REPEAT, the CASE, the WITH,
the WHILE, or the compound BEGIN-END statement) is entered during the scan of
the source code, the block depth of the procedure is incremented, and is
decremented upon exiting the structured statement.
0 PROGRAM Sample;
0 VAR I:Integer;
0
0 PROCEDURE This;
1 BEGIN
1 Write('This is just a sample.');
1 END;
0
1 BEGIN
2 FOR I:=1 to 10 DO
2 This;
1 Writeln;
1 END.
The 'Active Procedures' field, when activated ("ON"), will print the name
of the procedure or function (presently being scanned) to the right of the
output source code. The name is enclosed in brackets (between '{' and '}') to
increase the documentation effects of the source and to make it possible to
recompile the output source.
The following is an example of the program's output if this field was
activated. (This is also an excellent way to recognize new lines in version
updates to source files. Those lines added after a version is complete and
updated by T-Ref would not have this field at the end of the lines.)
8
PROGRAM Sample; { SAMPLE }
VAR I:Integer; { SAMPLE }
{ SAMPLE }
PROCEDURE This; { THIS }
BEGIN { THIS }
Write('This is just a sample.'); { THIS }
END; { THIS }
{ SAMPLE }
BEGIN { SAMPLE }
FOR I:=1 to 10 DO This; { SAMPLE }
Writeln; { SAMPLE }
END. { SAMPLE }
Any of the listable information described above may be combined in any
combination. Since the 'Line Numbers' field, the 'Lexical Levels' field, and
the 'Block Levels' field are printed to the left of the source for each line,
a combination of more than one of these will create a column for each one in
that specific order. For example, if all three fields are activated, the
output would be as follows:
1 1 0 PROGRAM Sample;
2 1 0 VAR I:Integer;
3 1 0
4 1 0 {$I This.Prc}
4 1 2 0 PROCEDURE This;
4 2 2 0
4 3 3 0 PROCEDURE Now_That;
4 4 3 1 BEGIN
4 5 3 1 Writeln;
4 6 3 1 END;
4 7 2 0
4 8 2 1 BEGIN
4 9 2 1 Write('This is just a sample.');
4 10 2 1 Now_That;
4 11 2 1 END;
5 1 0
6 1 1 BEGIN
7 1 2 FOR I:=1 to 10 DO This;
8 1 1 END.
The 'Header' field is used to activate ("ON") the inclusion of a header
to be printed at the top of each page of source output. The header can be
from two to five lines and each line can be up to 75 columns in length. The
F3 function key creates the header to be printed. If a header is printed, the
program will automatically buffer 3 blank lines before the header (the first
line of the new page) and 2 blank lines after the header (before the next line
of source code), so it is not necessary to buffer the header with blank lines
within the header itself.
The 'Page Numbering' field will, when activated ("ON"), automatically
number the pages of the output source (whether it is going to a file or to the
printer). A date/time tag is printed on the page number line, also. The
number of lines per page is set by the F6 function key. If page numbering is
deactivated ("OFF") and the output is going to a file, the source is contin-
9
uous with no blank lines between pages. If page numbering is deactivated and
the output is to the printer, the listing will automatically include three
blank lines at the end of each page and one blank line at the head.
NOTE: When both the 'Header' and 'Page Numbering' fields are turned "Off"
and the output is routed to a specified file (the 'Active Output File' field
is not blank), paging, that is blank lines between pages, will not occur.
Therefore, the output source is continuous. If either or both of these fields
are "On", paging will occur; whether output is to the printer or to a file.
NOTE: There are separate switches on headers and page numbering for the
source lister and the cross referencer. This feature was provided to allow
more flexible customized listing when run separately. When both a source
listing and cross reference listing are desired, we recommend you set these to
the same values. Since it is difficult to accurately assess all combinations.
Therefore, the output characteristics may differ from the desired results of
the listing if the above stated recommendation is not adhered to.
The 'Include File' field informs the program whether or not to print
external files (normally included in compilation through an include file
compiler directive (i.e., '{$I THIS.PRC}')) directly in with the main source
code. When activated ("YES"), include files are automatically placed into the
output's source listing immediately after the include file compiler directive
is interpreted. There is additionally an OPTIONAL setting ("OPT") which
allows you to selectively decide which include files are to be printed. When
this setting is used, a message is sent to the message area of the screen
every time an include file compiler directive is scanned, asking for deter-
mination as to whether the file is to be included in the source listing.
Responding "Y"es will route the include file source to the output; "N"o will
cause the include file source listing to be skipped.
10
