The COMIS compiler (source format).

The COMIS system language is an almost full implementation of FORTRAN 77. As the user is working in a realtime environment, some simplifications of the language syntax (in addition to the standard one) are also available: short forms for key-words (CHAR instead of CHARACTER and so on) and a free source code format.

The main differences between the COMIS syntax and standard FORTRAN 77 are:

COMIS does not accept:
- Character functions.
- Statement functions.
- INTRINSIC statements.
- ENTRY statements.
- BLOCK DATA statements.
COMIS does not allow a character type variable to be equivalenced with another character variable.
A type declaration statement, which define the data type of common block name's, must precede the COMMON statement.
The logical operators .EQV. and .NEQV. are not included in COMIS.
COMIS does not allow a character expression and an alternate return specifiers as actual arguments.

The source format

The COMIS source code is essentially free format. Extensions are:

Statements may start at any position.
More than one statement may be given per source line. In this case they should be separated by blank(s), or optionally by ';'.
A statement may occupy more than one source line without any special marks.
Source lines may be up to 80 characters long. Thus, source line numbering in columns 73-80 is not available.
A symbolic name is a string of letters, digits and underscore (_). The symbolic name may have any length, but significant characters are the first eight only.

Note

Blanks are meaningful in COMIS.
Comment lines are marked by '*' or 'C' in column one. An exclamation mark (!) starts an inline comment, except when it appears as the first non-blank character on a line.
Some extentions may cause a conflict with the conventions of FORTRAN 77.

IMPORTANT NOTE

Even if COMIS has a more flexible syntax than strandard FORTRAN, it is strongly recommended to stick to the genuine FORTRAN syntax. In particular always start your COMIS programs in column 7. If you start in column 1, all the statements starting with "C" will be considered as comments, in particular the statement COMMON.