chill.texi

gcc-2.95.3 Linux下最常用的C编译器

| @i{<buffer mode name>}
| @i{<text location>}
| @i{<text mode name>}
@end example
@end example

@b{semantics:}

@i{ADDR} is derived syntax for -> @i{<location>}.

@i{PRED} and @i{SUCC} delivers respectively, in case of a @i{discrete
expression}, the next lower or higher discrete value of their argument,
in case of @i{bound reference expression} these built-in calls deliver a
pointer to the previous or next element.

@i{ABS} is defined on numeric values, i.e. integer values and floating
point values, delivering the corresponding absolute value.

@i{LENGTH} is defined on

@itemize @bullet

@item string and text locations and string expressions, delivering the
length of them;

@item event locations, delivering the @b{event length} of the mode of the
location;

@item buffer locations, delivering the @b{buffer length} of the mode of
the location;

@item string mode names, delivering the @b{string length} of the mode;

@item text mode names, delivering the @b{text length} of the mode;

@item buffer mode names, delivering the @b{buffer length} of the mode;

@item event mode names, delivering the @b{event length} of the mode;

@item Additionally, @i{LENGTH} also may be used on the left hand
side of an assignment to set a new length of a @i{varying character
string location}. However, to avoid undefined elements in the varying
string, the new length may only be less or equal to the current length.
Otherwise a @b{RANGEFAIL} exception will be generated.
@end itemize

@i{SIN} delivers the sine of its argument (interpreted in radians).

@i{COS} delivers the cosine of its argument (interpreted in radians).

@i{TAN} delivers the tangent of its argument (interpreted in radians).

@i{ARCSIN} delivers the sin -1 function of its argument.

@i{ARCCOS} delivers the cos -1 function of its argument.

@i{ARCTAN} delivers the tan -1 function of its argument.

@i{EXP} delivers the exponential function, where x is the argument.

@i{LN} delivers the natural logarithm of its argument.

@i{LOG} delivers the base 10 logarithm of its argument.

@i{SQRT} delivers the sqare root of its argument.

@i{QUEUE_LENGTH} delivers either the number of sending delayed processes
plus the number of messages in a buffer queue (if the argument is a
@i{buffer location}), or the number of delayed processes (if the
argument specifies an @i{event location}) as @i{integer expression}.

@i{GEN_INST} delivers an @i{instance expression} constructed from the
arguments. Both arguments must have the @i{&INT}-derived class.

@i{COPY_NUMBER} delivers as @i{&INT}-derived class the copy number of an
@i{instance location}.

@i{GEN_PTYPE} delivers as @i{&INT}-derived class the associated number
of the @i{process name}.

@i{PROC_TYPE} delivers as @i{&INT}-derived class the process type of an
@i{instance expression}.

@i{GEN_CODE} delivers as @i{&INT}-derived class the associated number of
the @i{process name} or @i{signal name}.

@i{DESCR} delivers a @i{free reference expression} pointing to a
structure with the following layout describing the @i{location} argument.

@example
SYNMODE __tmp_descr = STRUCT (p PTR, l ULONG);
@end example


@item 7.4.2 Associating an outside world object@*
The syntax of the associate built-in routine call is defined as:

@example
@i{<associate built-in routine call> ::=}
@example
@i{ASSOCIATE ( <association location>, <string expression>,} [@i{, <string expression>} ] @i{)}
@end example
@end example

The ASSOCIATE call has two parameters besides the association location:
a pathname and an optional mode string.

The value of the first string expression must be a pathname according to
the rules of the underlying operating system. (Note that a relative pathname 
implies a name relative to the working directory of the process.)

The mode string may contain the value "VARIABLE", which requests
an external representation of records consisting of an UINT record
length followed by as many bytes of data as indicated by the length field.
Such a file with variable records is not indexable.

A file with variable records can be written using any record mode. If the 
record mode is CHARS(n) VARYING, the record length is equal to the actual 
length of the value written.  (Different record may have differing lengths.)
With all other record modes, all records written using the same access mode
will have the same length, but will still be prefixed with the length field.
(Note that by re-connecting with different access modes, the external
representation may ultimately contain records with differing lengths.)

A file with variable records can only be read by using a record mode of
CHARS(n) VARYING.


@item 7.4.2 Accessing association attributes@*
The value of the READABLE and WRITEABLE attributes is determined using 
the file status call provided by the operating system.  The result will
depend on the device being accessed, or on the file mode.

The INDEXABLE attribute has the value false for files with variable records,
and for files associated with devices not supporting random positioning
(character devices, FIFO special files, etc.).

The variable attribute is true for files associated with the mode sting
"VARIABLE", and false otherwise.


@item 7.4.5 Modifying association attributes@*
The syntax of the MODIFY built-in routine call is defined as:

@example
@i{<modify built-in call> ::=}
@example
@i{MODIFY ( <association location>, <string expression> )}
@end example
@end example

At present, MODIFY accepts a character string containing a pathname
in addition to the association location, which will cause a renaming 
of the associated file.


@item 7.4.9 Data transfer operations@*
READRECORD will fail (causing READFAIL) if the number of bytes from the
current position in the file to the end of the file is greater than zero
but less than the size of the record mode, and no data will be transferred.
(If the number of bytes is zero, no error occurs and OUTOFFILE will
return TRUE.)

The number of bytes transferred by READRECORD and WRITERECORD is equal to
the size of the record mode of the access location. Note that the
internal representation of this mode may vary depending on the
record mode being packed or not.


@item 7.5 Text Input Output@*
Sequential text files will be represented so as to be compatible
with the standard representation of texts on the underlying operating
system, where control characters are used to delimit text records on files
as well as to control the movement of a cursor or printing head on a device.

For indexed text files, records of a uniform length (i.e. the size of the
text record, including the length field) are written.  All i/o codes cause 
an i/o transfer without any carriage control  characters being added to the
record, which will be expanded with spaces.

An indexed text file is therefore not compatible with the standard
text representation of the underlying operating system. 



@item 7.5.3 Text transfer operations@*
The syntax of @i{<text argument>} is changed to:

@example
@i{<text argument> ::=}
@example
  @i{<text location>}
| @i{<predefined text location>}
| @i{<varying string location>}
@end example

@i{<predefined text location> ::=}
@example
  STDIN
| STDOUT
| STDERR
@end example
@end example

NOTE: The identifiers STDIN, STDOUT, and STDERR are predefined.
Association and connection with files or devices is done according to
operating system rules.

The effect of using READTEXT or WRITETEXT with a character string location
as a text argument (i.e. the first parameter) where the same location also
appears in the i/o list is undefined.

The current implementation of formatting assumes run-to-completion semantics
of CHILL tasks within an image.



@item 7.5.5 Conversion@*
Due to the implementation of @i{<floating point modes>} the syntax
is changed to:

@example
@i{<conversion clause> ::=}
@example
@i{<conversion code> @{ <conversion qualifier @} *}
@i{[ <clause width> ]}
@end example

@i{<conversion code> ::=}
@example
@i{B} | @i{O} | @i{H} | @i{C} | @i{F}
@end example

@i{<conversion qualifier> ::=}
@example
@i{L} | @i{E} | @i{P<character>}
@end example

@i{<clause width> ::=}
@example
  @i{@{ <digit> @} +} | @i{V}
| @i{<real clause width>}
@end example

@i{<real clause width> ::=}
@example
@i{@{ @{ <digit> + | V @} : @{ @{ <digit> @} + | V @}}
@end example
@end example

Note: The @i{<real clause width>} is only valid for @i{<conversion
code>} `C' or `F'.


@item 7.5.7 I/O control@*
To achieve compatibility of text files written with CHILL i/o with
the standard representation of text on the underlying operating system
the interpretation of the i/o control clause of the format 
deviates from Z.200. The following table shows the i/o codes together
with the control characters written before and after the text record, 
to achieve the indicated function:
@table @samp
@item /
Write next record (record, line feed)

@item +
Write record on next page (form feed, record, line feed)

@item -
Write record on current line (record, carriage return)

@item ?
Write record as a prompt (carriage return, record)

@item !
Emit record (record).

@item =
Force new page for the next line: The control character written before
the next record will be form feed, irrespective of the i/o control used for
transferring the record.
@end table

When reading a text file containing control characters other than line feed,
these characters have to be reckoned with by the format used to read the
text records.




@item 11.2.2 Regionality@*
Regionality is not implemented at all, so there is no difference in the
generated code when REGION is substituted by MODULE in a GNUCHILL
compilation unit.

@item 11.5 Signal definition statement@*
The @i{<signal definition statement>} may only occur at module level.

@item 12.3 Case Selection@*
The syntax of @i{<case label specification>} is changed to:

@example
@i{<case label specification> ::=}
@example
@i{( <case label> @{, <case label> @} * )}
@end example

@i{<case label> ::=}
@example
  @i{<discrete literal expression>}
| @i{<literal range>}
| @i{<discrete mode name>}
| @b{ELSE}
@end example
@end example

@end itemize

@node Directives
@chapter Compiler Directives

@itemize @bullet

@item ALL_STATIC_ON, ALL_STATIC_OFF@*
These directives control where procedure local variables are
allocated. ALL_STATIC_ON turns allocation of procedure local variables
in the data space ON, regardless of the keyword STATIC being used or not.
ALL_STATIC_OFF places procedure local variables in the stack space.
The default is ALL_STATIC_OFF.

@item RANGE_ON, RANGE_OFF@*
Turns generation of rangecheck code ON and OFF.

@item USE_SEIZE_FILE <character string literal>@*
Specify the filename (as a character string literal) where 
subsequent SEIZE statements are related to. This directive 
and the subsequent SEIZEs are written
to a possibly generated grant file for this module.

@example
<> USE_SEIZE_FILE "foo.grt" <>
SEIZE bar;
@end example

@item USE_SEIZE_FILE_RESTRICTED "filename"@*
Same as USE_SEIZE_FILE. The difference is that this directive
and subsequent SEIZEs are *not* written to a possibly generated
grant file. 

@item PROCESS_TYPE = <integer expression>@*
Set start value for all PROCESS delclarations. This value automatically
gets incremented after each PROCESS declaration and may be changed with
a new PROCESS_TYPE compiler directive.

@item SIGNAL_CODE = <integer expression>@*
Set start value for all SIGNAL definitions. This value automatically
gets incremented after each SIGNAL definition and may be changed with a
new SIGNAL_CODE compiler directive.

@item SEND_SIGNAL_DEFAULT_PRIORITY = <integer expression>@*
Set default priority for send signal action.

@item SEND_BUFFER_DEFAULT_PRIORITY = <integer expression>@*
Set default priority for send buffer action.

Note: Every <integer expression> in the above mentioned compiler
directives may also be specified by a SYNONYM of an integer type.

@example
SYN first_signal_code = 10;
<> SIGNAL_CODE = first_signal_code <>
SIGNAL s1;
@end example

@end itemize

@node References
@chapter Language Definition References

@itemize @bullet
@item	CCITT High Level Language (CHILL) Recommendation Z.200
	ISO/IEC 9496, Geneva 1989                ISBN 92-61-03801-8

@item	An Analytic Description of CHILL, the CCITT high-level
	language, Branquart, Louis & Wodon, Springer-Verlag 1981
                                                 ISBN 3-540-11196-4

@item	CHILL User's Manual
	CCITT, Geneva 1986                       ISBN 92-61-02601-X

@item	Introduction to CHILL
	CCITT, Geneva 1983                       ISBN 92-61-017771-1

@item	CHILL CCITT High Level Language
	Proceedings of the 5th CHILL Conference
	North-Holland, 1991                      ISBN 0 444 88904 3

@item	Introduction to the CHILL programming Language
	TELEBRAS, Campinas, Brazil 1990

@end itemize

Z.200 is mostly a language-lawyer's document, but more readable
than most.  The User's Guide is more readable by far, but doesn't
cover the whole language.  Our copies of these documents came through
Global Engineering Documents, in Irvine, CA, USA. [phone].

@contents
@bye