NAME

efl − Extended Fortran Language

SYNOPSIS

efl [ options ] [ files ]

DESCRIPTION

Efl compiles a program written in the EFL language into clean Fortran on the standard output.  Efl provides the C-like control constructs of ratfor(1):

statement grouping with braces. 

decision-making:
if, if-else, and select-case (also known as switch-case);
while, for, Fortran do, repeat, and repeat ... until loops;
multi-level break and next. 

EFL has C-like data structures, e.g.:

struct

{
integer flags(3)
character(8) name
long real coords(2)
} table(100)

The language offers generic functions, assignment operators (+=, &=, etc.), and sequentially evaluated logical operators (&& and ││). There is a uniform input/output syntax:

write(6,x,y:f(7,2), do i=1,10 { a(i,j),z.b(i) })

EFL also provides some syntactic “sugar”:

free-form input:
multiple statements per line; automatic continuation; statement label names (not just numbers).

comments:
# this is a comment. 

translation of relational and logical operators:
>, >=, &, etc., become .GT., .GE., .AND., etc. 

return expression to caller from function:
return (expression)

defines:
define name replacement

includes:
include file

Efl understands several option arguments: −w suppresses warning messages, −# suppresses comments in the generated program, and the default option −C causes comments to be included in the generated program. 

An argument with an embedded = (equal sign) sets an EFL option as if it had appeared in an option statement at the start of the program.  Many options are described in the reference manual.  A set of defaults for a particular target machine may be selected by one of the choices: system=unix, system=gcos, or system=cray.  The default setting of the system option is the same as the machine the compiler is running on.  Other specific options determine the style of input/output, error handling, continuation conventions, the number of characters packed per word, and default formats. 

Efl is best used with f77(1).

SEE ALSO

cc(1), f77(1), ratfor(1). 
The Programming Language EFL by S.I. Feldman. 

May 16, 1980