Category:PL/I: Difference between revisions

Added tags=pli
No edit summary
(Added tags=pli)
 
(10 intermediate revisions by 6 users not shown)
Line 1:
{{stub}}{{language|PL/I}}
{{language|PL/I
<lang>
|exec=machine
|strength=strong
|safety=safe
|compat=nominative
|express=explicit
|checking=static
|parampass=both
|tags=pli
|gc=no
|LCT=yes
|tags=pli}}
{{language programming paradigm|Imperative}}
 
PL/I is a general purpose programming language suitable for commercial, scientific, non-scientific, and system programming.
 
 
It provides the following data types:
 
::* &nbsp; Floating-point,
::* &nbsp; Decimal integer,
::* &nbsp; Binary integer,
::* &nbsp; Fixed-point decimal &nbsp; (with a fractional part),
::* &nbsp; Fixed-point binary &nbsp; (that is, with a fractional part),
::* &nbsp; Pointers,
::* &nbsp; Character strings of two kinds:
1. fixed-length, and
::::# &nbsp; 2. varyingfixed-length., &nbsp; and
::::# 2.&nbsp; varying -length.
::* &nbsp; Bit strings of two kinds:
1. fixed-length, and
::::# 1.&nbsp; fixed-length, &nbsp; and
2. varying length.
::::# &nbsp; varying length.
 
<br>
The &nbsp; float, &nbsp; integer, &nbsp; and &nbsp; fixed-point &nbsp; types can be &nbsp; real &nbsp; or &nbsp; complex.
 
The float, integer,and fixed-point types can be real or complex.
 
Multiple precisions are available for binary fixed-point:
::* &nbsp; 8 bits,
typically using 8 bits, 16 bits, 32 bits, and 64 bits.
::* &nbsp; 16 bits,
::* &nbsp; 32 bits, &nbsp; and
::* &nbsp; 64 bits.
 
 
Multiple precisions are available for floating point:
::* typically using&nbsp; 32 bits, 64 bits, and 80 bits.
::* &nbsp; 64 bits, &nbsp; and
::* &nbsp; 80 bits.
 
 
The language provides for static and dynamic arrays. &nbsp; Of the latter, there are &nbsp; automatic, &nbsp; controlled, &nbsp; and &nbsp; based.
Controlled can be applied to any data type, including scalar, structure, as well as arrays. &nbsp; With controlled, a push-down and pop-up stack is automatically used.
 
The language provides for static and dynamic arrays.
Of the latter, there are automatic and controlled.
Controlled can be aplied to any data type, including
scalar, structure, as well as arrays.
With controlled, a push-down and pop-up stack is automatically used.
 
PL/I has four kinds of I/O:
::# &nbsp; For simple I/O commands, list-directed input and output requires only the names of the variables. &nbsp; Default format is used, based on the variable's declaration.
::# &nbsp; For simple I/O commands, data-directed input and output requires only the names of the variables. &nbsp; For this form, both the names of the variables and their values are transmitted.
::# &nbsp; When precise layouts of input and output data is required, edit-directed I/O is used. &nbsp; A format is specified by the user. &nbsp; The format is flexible, and permits the number of digits, and the number of places after the decimal point to be specified dynamically. &nbsp; The format may also be specified in picture form.
Default format is used, based onthe variable's declaration.
::# &nbsp; For files held on storage media, record-oriented transmission is often used, either for &nbsp; sequential &nbsp; or &nbsp; random access.
For simple I/O commands, data-directed input and output
 
requires only the names of the variables. For this form,
 
both the names of the variables and their values are transmitted.
PL/I has built-in checking for such programmer conditions including
When precise layouts of input and output data is required,
::* including&nbsp; subscript-range checking, floating-point overflow,
edit-directed I/O is used. A format is specified by the user.
::* &nbsp; floating-point overflow,
The format is flexible, and permits the number of digits, and
::* &nbsp; fixed-point overflow,
the number of places after the decimal point to be specified
::* &nbsp; division by zero,
dynamically. The format may also be specified in picture form.
::* &nbsp; sub-string range checking, &nbsp; and
for files held on storage media, record-oriented transmission
::* &nbsp; string-size checking.
is often used, either for sequential or random access.
 
<br>
and stringsize checking. Any of those may be enabled or disabled by the user.
 
When any of those conditions occurs, the user/programmer may trap them and recover from them and continue execution.
 
PL/I has a unique and powerful pre-processor which is a subset of the full PL/I language so it can be used to perform &nbsp; (among other things):
PL/I has built-in checking for such programmer conditions
::* &nbsp; source file inclusion,
including subscript-range checking, floating-point overflow,
::* &nbsp; conditional compilation, &nbsp; and
fixed-point overflow, division by zero, substring range checking,
::* &nbsp; macro expansion.
and stringsize checking. Any of those may be enabled or disabled
by the user.
 
<br>
When any of those conditions occurs, the user may trap them and
The pre-processor keywords are prefixed with a &nbsp; <big>%</big> &nbsp; (percent symbol).
recover from them and continue execution.
</langbr><br>
==See Also==
* [[wp:PL/I|PL/I on Wikipedia]]
* [[PL/M]]
* [[Polyglot:PL/I and PL/M]]
3,044

edits