.TH STRUCT 1
.SH NAME
struct \- structure Fortran programs
.SH SYNTAX
.B struct
[ option ] ...
file
.SH DESCRIPTION
.I Struct
translates the Fortran program specified by
.I file
(standard input default)
into a Ratfor program.  Wherever possible, Ratfor control constructs
replace the original Fortran.  Statement numbers appear only where
still necessary.
Cosmetic changes are made, including changing Hollerith strings
into quoted strings
and relational operators into symbols (.e.g. `.GT.' into `>').
The output is appropriately indented.
.PP
The following options may occur in any order.
.TP
.B  \-s
Input is accepted in standard format, i.e.
comments are specified by a \fBc\fP, \fBC\fP, or \fB*\fP in column 1, and
continuation lines are specified by a nonzero, nonblank character in column 6.
Normally, a statement whose first nonblank character
is not alphanumeric is treated as a continuation.
.TP
.B  \-i
Do not turn computed goto statements into
switches.
(Ratfor does not turn switches back
into computed goto statements.)
.TP
.B  \-a
Turn sequences of else ifs into a
non-Ratfor switch of the form:
.IP
.nf
.ta 5 7
switch {
		case pred1: code
		case pred2: code
		case pred3: code
		default: code
	}
.fi
.DT
.IP
The case predicates are tested in order;
the code appropriate to only one case is executed.
This generalized form of switch statement does not
occur in Ratfor.
.TP
.B  \-b
Generate goto's instead of multilevel break statements.
.TP
.B  \-n
Generate goto's instead of multilevel next statements.
.TP
.TP
.BI \-e n
If 
.I n
is 0 (default),
place code within a loop only if it can
lead to an iteration of the loop.
If
.I n
is nonzero,
admit code segments with fewer than
.I n
statements to a loop
if otherwise the loop would have exits to several places including the segment,
and the segment can be reached only from the loop.
.SH FILES
/tmp/struct*
.br
/usr/lib/struct/*
.SH SEE ALSO
f77(1)
.SH BUGS
\fIStruct\fP knows Fortran 66 syntax, but not full Fortran77
(alternate returns, IF...THEN...ELSE, etc.)
.br
If an input Fortran program contains identifiers which
are reserved words in Ratfor, the structured
version of the program
will not be a valid Ratfor program.
.br
Extended range DO's generate cryptic errors.
.br
Columns 73-80 are not special even when
.B \-s
is in effect.
.br
Will not generate Ratfor FOR statements.
.br
Has been known to give core images on large files. Making
them smaller helps.
.br
Long computed goto statements are sometimes transformed
improperly into switches.