INDENT -- SAIL SOURCE PROGRAM INDENTER











      INDENT  reads any  SAIL  program file,  producing  a file
      containing the same program in a standard format.


                                                  Dan Swinehart
                                                9 January, 1972

                                                                   1



                              SECTION I
                            USING INDENT

I-A. ____________     Capabilities

INDENT produces a properly  indented SAIL program, if your  notion of
proper indentation coincides with mine.  Otherwise it produces a SAIL
program  indented  in  a  standard  fashion  according  to  a  set of
hopelessly inadequate rules.

Leading spaces and tabs are  removed from all input lines.   Then new
lines are formed, and indentation rules applied, when:

  1. BEGINs and ENDs are seen (indentation changes here)

  2. Any input line becomes too long

  3. A new line appears in the input file


A "Block Indentation" parameter exists which determines the number of
extra spaces added to each line after a (type 1) BEGIN line until the
matching END is seen.

A "Continuation" line is a type 2 line, or any non-type 1  line, when
the preceding line does not end in ";", ",", etc.  Continuation lines
are  indented  by an  additional  amount equal  to  the "Continuation
Indentation" parameter.

Special  rules are  applied to  Comment lines,  and to  certain other
constructs.

I-B. _______ ______     Running Indent

Type "R INDENT"  to run the program.   An asterisk will  appear.  The
command format is the standard  one for processors which are  not run
via COMPILE, DEBUG, etc., to wit:

<output file>←<input file><switch list>.  Each switch is  preceded by
a  slash  ("/"),  or  a  number  of  switches  may  be   enclosed  in
parentheses.   A  switch is  (sometimes)  a number,  then  (always) a
letter.  Switches are  used to set the  above parameters, as  well as
some others.

The default output  file extension (if  none is specified)  is "SA1".
The default input file extension is "SAI".  If something  goes wrong,
see me.

USING INDENT                                                       2



I-C. ________     Switches

Let `d' be a decimal number, `o' an octal number.

SWITCH DEFAULT  MEANING

 dI      3      This is the Block-Indentation parameter.  The text of
                 each block and compound statement will  be  indented
                 `d' spaces from the next outer block.

 dO      1      The Continuation-Indentation parameter.

 dB      0      The left margin.  You can start at some column other
                 than 1 so that files can later be merged.

 dL     75      Max line length before a continuation line is forced.

 dD      0      Depth -- no indentation will occur at all until BEGIN
                 nesting reaches this depth. Thus, if your program
                 has many initial outer blocks before the important
                 stuff begins, you can inhibit unwanted indentation.

 oC      0      The octal code for a character to serve as an "As is"
                 character.  No text between two occurrences of this
                 character will be subject to indentation.  It will
                 be passed to the output file "as is".  This
                 character should be "DEFINE"d as some harmless
                 thing (like space) so that SAIL won't complain.

  T             Output will be typed on your console.  Omit the
                  "output file" spec in the command string.

                                                                   3



                             SECTION II
                               EXAMPLE

The command is: CHG←CHG(5B4I2O)

File CHG.SAI:

BEGIN "CHG"
INTEGER BRK,EOF,FLAG;STRING S;

DEFINE
INF="1",
OUTF="2",
TAB="1";
SETBREAK(1,"{}"&'177&'21,NULL,"IN");

COMMENT Get the input;

LOOKUP(INF,INCHWL,FLAG);
OUTSTR("OUTPUT FILE ");
"Get the Output"
ENTER(OUTF,INCHWL,FLAG);
WHILE TRUE DO BEGIN
OUT(OUTF,IF BRK="{" THEN "[" ELSE IF
BRK="}" THEN "]" ELSE IF
BRK='21 THEN '12 ELSE BRK)
END;
END "CHG";

EXAMPLE                                                            4



File CHG.SA1:

     BEGIN "CHG"
         INTEGER BRK,EOF,FLAG;STRING S;

         DEFINE
           INF="1",
           OUTF="2",
           TAB="1";
         SETBREAK(1,"{}"&'177&'21,NULL,"IN");

     COMMENT Get the input;

         LOOKUP(INF,INCHWL,FLAG);
         OUTSTR("OUTPUT FILE ");
     "Get the Output"
         ENTER(OUTF,INCHWL,FLAG);
         WHILE TRUE DO BEGIN
             OUT(OUTF,IF BRK="{" THEN "[" ELSE IF
               BRK="}" THEN "]" ELSE IF
                 BRK='21 THEN '12 ELSE BRK)
         END;
     END "CHG";