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1.1 Utilization

In the simplest case, the data format is analogous to that of a "list directed read" in Fortran 77( This type of read is obtained by replacing the format by a star, as in:

READ (UNIT,*) ...): it corresponds to a string of constants separated by one or several blanks. Each constant must be wholly contained within a record and is situated between columns 1 and 72 inclusively. In addition, the MODULEF free format offers a large number of supplementary possibilities:

• insert comments in the data,
• replace a data item by an arithmetic expression,
• use variables,
• call commands.

The following sections describes the above notions.

1.1.1 Constants

The format of the constants are very similar to that of Fortran. Consequently, only a few examples are given below. Depending on the case, the user must enter:

an integer:

36 -123

a single precision real:

12 12. 12.0 0.012E3

a double precision real:

12 12. 12.0 0.012D3

a complex:

A complex number is read like two consecutive single precision real numbers. For example, the complex number 3.5 + 7.9 i is obtained by reading the two real numbers:
3.5 7.9

a logical:

TRUE T YES Y
FALSE F NO N

It is possible to add a point at the beginning or at the end:

.TRUE. .T FALSE.

a character string:

One of the formats of a character string is the same as in Fortran: the string is delimited by apostrophes; any apostrophe contained within the string is represented by two consecutive apostrophes:

'EXAMPLE OF A STRING' 'IT''S EASY'

The other form corresponds to not delimiting the string by apostrophes, on condition that the string does not contain any (blanc), ', $, -- or // characters, and does not start by a ! or % character:

EXAMPLE3

1.1.2 Comments

Comments are ignored by the program, however, they promote understanding by the human reader. In its most usual form, a comment begins with two consecutive dashes and ends with an end-of-line:

3 -- NUMBER OF CURVED LINES
0.5 -- RADIUS OF THE CIRCLE

The other format is older but remains compatible with the previous one. It is less accommodating, especially when commenting a line already containing comments. In this format, each comment is delimited on the left by a dollar character ($) and on the right by a dollar character or an end-of-line:

1 2 3 $FIRST COMMENT$ 4 5 6 $SECOND COMMENT$ 7

1 2 3 4 5 6 7 $COMMENT AT THE END OF A LINE

1.1.3 Expressions

Instead of the classical constant (section 1.1.1), the user can input a numerical or character expression:

• If the data is numeric, all classical operators are admissible (+ - * / **). The known Fortran functions are: ABS, ACOS, ASIN, ATAN, ATAN2, COS, EXP, INT, LOG, LOG10, MOD, NINT, SIGN, SIN, SQRT, TAN. Lastly, the constant, PI, returns an approximate value of . No matter what the the type of operand is, the computation is done using double precision (for example, is evaluated as , and the result, 0.5D0, is converted to the variable type.

  Blanks and "carriage-returns" are forbidden, except in expression between parentheses.

  For example:

  3.85*1.42 ( 1 / 3 ) SQRT(3)/2 PI/2
  

  -- THE 4 VALUES READ ARE : 5.46700 0.333333 0.866025 1.57080

• With regard to character strings, only the concatenation operator, //, is admissible. It is used when a string is split over several lines. The total length of the string is nevertheless limited to 256 characters. For example:

  A//B

  'DAY '//

  'AND NIGHT'
  

  -- THE 2 STRINGS READ ARE : 'AB' 'DAY AND NIGHT'

1.1.4 Variables

It is possible to assign a value to a variable and then to use the same variable in an expression.

The syntax is as follows:

!<variable>=<expression>

where:

!

is an exclamation mark, preceding most commands (section 1.1.5).

<variable>

is the variable name. It may contain letters, numbers, underscore characters (_) and points (.), but may not start with a number. It is truncated to 12 characters if it exceeds this length. It may not be a predefined name: function name (section 1.1.3), constant name (section 1.1.3), or command name (section 1.1.5). Lastly, if the host computer employs upper- and lower-case letters, they are differentiated.

=

is the assignment symbol.

<expression>

is an expression (section 1.1.3).

All variables are converted to double precision.

Some commands are directly linked to using variables, namely !DUMP and <variable>=? (section 1.1.5). For example:

!R=1
!ALPHA=PI/3
R*COS(ALPHA)

-- THE VALUE READ IS : 0.5

1.1.5 Commands

Before entering the data, we can initiate a command. Most commands begin with an exclamation mark (!). Certain older commands, beginning with a percentage character (%), have been conserved for compatibility.

!ADRESSAGE

prints a message each time a dynamic array is allocated.

!NOADRESSAGE suppresses this effect.

!BAVARDAGE <expression>

modifies the MODULEF print parameter (from 0 to 10: the higher this value, the more output obtained).

!DEBUGING,

(normally not used!)

!DUMP

prints the name and value of each variable.

!ECHO

prints each line read.

!NOECHO suppresses this effect.

!ECRIRE <file>

(or !IMPRIMANTE <file>) writes all output to a file. If <file> is the character *, the write is directed to the initial printer. If <file> is the name of a file which exists already, it will be deleted.

!IDEM

do not modify the value of the variable to read. If the calling program has previously assigned a value by default, this value will be conserved.

!IMPRIMANTE <file>

: see !ECRIRE.

!LIRE <file>

reads input from a file. If <file> is the character *, the read is done from the initial input device. A read file can itself contain !LIRE commands. The command !RETOUR or an end-of-file returns to the previous file.

!NOADRESSAGE

: see !ADRESSAGE.

!NOECHO

: see !ECHO.

!NOSOUFFLEUR

: see !SOUFFLEUR.

!NOTRACE

: see !TRACE.

!RETOUR

: see !LIRE.

!SOUFFLEUR

print, before each read, the type of data requested.

!NOSOUFFLEUR suppress this effect.

!TERMINAL <expression>

change the type of MODULEF terminal (hardly ever used): 0 batch, 1 alphanumerics terminal, 2 graphics terminal.

!TRACE <file>

recopy onto file all that is typed on the initial input device.

!NOTRACE suppress this effect.

!TRACEBACK

print the name of every file open (in free format or other).

!<variable>=<expression>

evaluate an expression and assign the result to a variable (section 1.1.4).

!<variable>=?

request the value of a variable from the user.

!!<system command>

initiate a host system command. If the command contains one or several blanks, it must be delimited by apostrophes. For example, in Unix, !!ls or !!'ls -lg' prints the contents of a directory.

The old commands, starting with the character, %, have been conserved so that all the existing data sets remains usable. In fact, it suffices to type only the beginning of these commands, until there are a sufficient amount of characters to avoid any ambiguity (for example: %R). In the listing below, the arrow ( ) indicates the name of the new equivalent command, if it exists.

%ADRESSAGE n

: !ADRESSAGE ; n = 0 !NOADRESSAGE.

%BAVARDAGE n

!BAVARDAGE n.

%ECHO n

: n = 1 !ECHO ; n = 0 !NOECHO.

%IMPRIMANTE n

: !ECRIRE <file>, where <file> is the name of the file with logical number n ; n < 0 !ECRIRE *.

%LECTEUR n

!LIRE <file>, where <file> is the name of the file with logical number n. In all cases, %LECTEUR is usable with a file which is already open (and reads therefore at the end of the last data read), whereas !LIRE is not.

%OUVRIR n

!LIRE <file>, where <file> is the name of the file with logical number n.

%RETOUR

!RETOUR.

%SAUVER n

!TRACE <file>, where <file> is the name of the file with logical number n.

%SOUFFLEUR n

: n = 1 !SOUFFLEUR ; n = 0 !NOSOUFFLEUR.

%TERMINAL n

!TERMINAL n.

%?

: outputs the type of data requested (see also %SOUFFLEUR).