CCSL Free Format Input

In order to avoid FORTRAN fixed format READ statements, CCSL contains a number of free format routines. These routines are used to read information from the Crystal Data. Each card is read initially as a string of (up to) 80 characters. These are then interpreted by CCSL routines like:

RDINTG

read next integer ,

RDREAL

read next real number,

RDWORD

read next word .

Definitions for Free Format Items

We define three types of item to read: integers, reals and words.

An integer is a (possibly signed) sequence of digits.

A real is a (possibly signed) sequence of digits, possibly containing one decimal point, or possibly containing one slash. The exponential format: a (possibly signed) sequence of digits, containing one decimal point followed by an "E" followed by a (possibly signed integer) is now allowed.

A word is a sequence of characters starting with a letter.

All three items are terminated by a space or the line end; integers and reals are also terminated by a comma. Surplus spaces are allowed.

Examples

Integers

6 10 -4 99999, 42, 3

Reals

12.34 92 5/12 -6.78904, -3, , -12.E5

Words

Fred Ca14 This-is-one-long-word

Not integers

3. 12/4 -4-3

Not reals

5./12 4.E2.5 67.89*

Not words

1Fred *JIM

Special Words

Many of the routines in CCSL recognise special words of up to four characters which are found in the Crystal Data. Some commonly used types are:

atom-label

A word used to identify a particular atomic site;

scattering-factor-label

A word used to identify a particular form factor;

CCSL-word

A word whose meaning is defined within CCSL.