93.2100E-05 according to the specification 2PE18.4*. Unlike an F
number, the <emphasis> value </emphasis> is the same in either
case.</para>
+
+</sect3>
+<sect3><title>Multiple Specifications</title>
+
+<para>Several specifications may be condensed into one larger one by the use
+of the character "/". Each appearance of "/" (except as part of a
+Hollerith field-see section 2.15.8) indicates that the specification
+of a new line (or card) is to be started with what follows. A pair
+"//" causes a blank line (or card), three "///" cause two blank lines
+(or cards), etc. Thus, the specification</para>
+
+<para role='centered'>
+3F10.3/I2, K18, 2C5/7I3*
+</para>
+
+<para>implies that one line (or card) is described by the specification
+3F10.3, and the next line (or card) is described by the specification
+I2,K18,2C5, and the next by 7I3. It must be noted that each line (if
+printing is being described) is described individually here, and must
+<emphasis> include its own carriage control </emphasis> (see section
+2.15.1).</para>
+
+</sect3>
+<sect3><title>Hollerith fields</title>
+
+<para>Although the C specification is available for transmitting
+characters (Hollerith information) to and from storage, it is often
+convenient to include strings of Hollerith characters directly in the
+format specification. This is done by means of a basic Hollerith
+field specification consisting of the string of characters to be
+transmittted, preceded by a count of these characters and the letter
+"H". Thus, if the specification</para>
+
+<para role='centered'>
+1H1 F10.3, 6HBETA = E10.2
+</para>
+
+<para>were used in printing one would obtain a new page skip, because of the
+one column Hollerith field containing the character "1". Then a ten
+column F number would print, followed by the characters "BETA =" and a
+floating point ten column field. Note that blanks are completely
+ignored throughout all format specifications except when they occur as
+characters in a Hollerith string. Note also, that while every field
+specification of types S, I, E, F, K, and C must be followed by
+commas, the comma may be omitted after a Hollerith string of the type
+described here. The comma may be used, however, if desired.</para>
+</sect3>
+
+<sect3><title>Character fields</title>
+
+<para>It has been stated above that a <emphasis> number </emphasis>
+appearing in an oversize field is pushed as far as possible to the
+<emphasis> right</emphasis>. In the case of C information
+(characters), any information occurring in an oversize field is pushed
+to the <emphasis> left </emphasis>, while in either case, unused
+columns of the field are filled with blanks. Similarly, in the case
+the specification describes too small a field, characters are taken
+from the <emphasis> left end </emphasis> of the field until the field
+is exhausted.</para>
+
+<para>Thus, if a card contins the characters: ABCDEFGHIJK in column 1
+through 11, and it is read according to the specification 2C3*, the
+two six character words that are read into the computer are:</para>
+
+<literallayout>
+ ABC□□□
+ DEF□□□
+</literallayout>
+
+<para>(where "□" denotes "blank"), while the specification C6* would
+cause a single word to be read:</para>
+
+<para role='centered'>
+ABCDEF
+</para>
+
+<para>and C7, C3* would cause the words:</para>
+
+<para role='centered'>
+ABCDEF and HIJ□□□
+</para>
+
+<para>to be read (since at most six characters can go into one word of
+storage).</para>
+
</sect3>
+<sect3><title>Relationship between the List and the Specification</title>
+
+<para>The "list" consists of a set of names of variables to or from which
+information is to flow. Except for Hollerith strings imbedded in the
+format specification itself (see section 2.15.8) and the S fields,
+each field in the specification refers to one item on the list. For
+this purpose, a regional entry on the list, such as A(6) ...A(8),
+counts as several names of variables (in this case, the three
+variables A(6), A(7), and A(8).) During the transmission of
+information, the input or output subroutine scans both the list and
+the specification simultaneously, correlating corresponding entries,
+and associating a field size, a type of conversion, etc. to each
+variable. If a Hollerith string is encountered in the specification,
+it is immediately transmitted, and it is not associated with any item
+on the "list."</para>
+
+<para>For example, if the list consisted of:</para>
+
+<para>A, B(1,1), I, K, where I and K were integers, and the others floating
+point, and the specification was</para>
+
+<para role='centered'>
+1H1, F11.3, -2PE14.4, S13, 3HM =I3, S9, 3HJ =I3*
+</para>
+
+<para>we might find a printed line something like the following (at the top of the next page because of the 1H1):</para>
+
+<para role='centered'>
+456.010 -16.1251E+02 M = 50 J = 17
+</para>
+
+<para>The same list would look the following way with the
+specification 1H1, 2F11.3, S16, 3HM =I3, S9, 3HJ = 13*:</para>
+
+<para role='centered'>
+456.101 -1612.510 M = 50 J = 17
+</para>
+
+<para>As stated above, a specification may not account for more than 72
+columns on a card. It may happen, however, that a list calls for more
+information than can appear on a single card. Or perhaps only a
+certain part of each card is to be read. The determining factor in
+every case is whether or not the entire list has been accounted for.
+After each cards is read according to the format specification, the
+list is consulted; if not yet satisfied, another card is read, and so
+on. It is important to realize that the specification is not
+necessarily scanned from the beginning when a new card is read. In
+fact, the specification scanner moves to the left from the end of the
+specification (the *) until it hits a left parenthesis not in an H
+field. (If there is no left parenthesis, it will move to the
+beginning of the specification). It then examines the characters just
+to the left of this left parenthesis to see if they are a multiplicity
+indication (see section 2.15.5). From this left parenthesis (together
+with the multiplicity, if any) to the end of the specification now
+becomes the format specification until the list is satisfied. A
+similar statement may be made for printed or punched output.</para>
+
+<para>Thus, in the specification:</para>
+
+<para role='centered'>
+3F10.3 /4(F10.3, 6HBETA = I2)*
+</para>
+
+<para>the first line printed (or read) would have three fixed point numbers,
+subsequent lines would all be printed (or read) according to the
+specification</para>
+
+<para role='centered'>
+4(F10.3, 6HBETA =I2)*
+</para>
+
+<para>As an example, one might have an integer on a first data card,
+followed by many cards, each with six floating point numbers. The
+specification might then be:</para>
+
+<para role='centered'>
+I6/(6E10.5)*
+</para>
+
+<para>Only the first six columns would be read on the first cards, and only
+60 columns would be read on subsequent cards. The remaining columns
+are ignored and may contain any <emphasis> legitimate </emphasis>
+Hollerith characters.</para>
+
+<para>If a specification contains a Hollerith string of the form
+nHa_1a_2...a_n, certain conventions are observed. (1) If the list is
+satisifed, but the next field specification is a Hollerith string, the
+string is transmitted, anyway. (2) On input, i.e., reading from
+cards, when a Hollerith string is encountered in the specification,
+the information in the corresponding columns of the input card will be
+brought in and will replace the BCD string itself within the format
+specification. This can then be used as a specification for output,
+for example. This is useful for labelling a set of data and causing
+the label to appear on the output along with a date, etc.</para>
+
+<para>Thus, a card punched as follows:</para>
+
+<para role='centered'>
+1 DATA SET NO. 3-A JULY 31, 1959 J. DOE
+</para>
+
+<para>might be read in with a format specification</para>
+
+<para role='centered'>
+72H (72 blank spaces) *.
+</para>
+
+<para>Later, this specification could be used to print the same information
+as a heading for the results. Note the "1" provided for carriage
+control for the printing.</para>
+
+<para>WARNING: The specifications S72* and 72(1H )*, while indicating 72
+blank spaces, do not allow the reading in of an entire card, as
+indicated above, since they do not really provide a storage region of
+72 characters in length into which the information on the card may be
+read and stored until needed.</para>
+</sect3>
+</sect2>
+</sect1>
+
+<sect1><title>Declarations (Non-executable statements)</title>
+
+<para>Declarations are non-executable statements, and, except for function
+declarations, they may occur anywhere in the program. Their purpose
+is to furnish information to the translator program or to the reader
+of the program. Declarations may have statement labels, but these
+labels are ignored by the translator, and may not be referred to in
+other statements.</para>
+
+<sect2><title>Remark Declaration</title>
+
+<para>A remark declaration consists of any string of characters
+acceptable to the computer. This statement is completely ignored by
+the translator, and furnishes information to the reader of the
+program. Every card of the remark declaration must have an "R" in
+column 11.</para>
+
</sect2>
</sect1>
</chapter>
projects / mad.git / commitdiff