Standard Pascal: what changed

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Title: Standard Pascal

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1	+	In 1974, the creator of the [[Pascal]] language, [[Niklaus Wirth]] wrote a book with Kathleen Jensen, titled [[Pascal User Manual and Report]] published by Springer-Verlag. This book became a de-facto standard for the Pascal language. In 1983 the International Standards Organization (ISO) formalized the de-facto standard as ISO 7185:1983. In 1990 ISO released an updated version - ISO 7185:1990 - that didn't introduce any new concepts, but cleared up ambiguities and corrected errors that were in the earlier version. The ISO 7185 standard is referred to as Standard Pascal. The standard defines the minimum level that a [[Compiler\|Pascal compiler]] must support in order to be a true compiler of the Pascal language.
2	+
3	+	## [[Reserved word\|Reserved Words]]
4	+
5	+	The following are the standard [[Keyword\|keywords]] (referred to as word-symbols in the ISO 7185) that all compilers must support:
6	+
7	+	- [[And\|and]]
8	+	- [[Array\|array]]
9	+	- [[Begin\|begin]]
10	+	- [[Case\|case]]
11	+	- [[Const\|const]]
12	+	- [[Div\|div]]
13	+	- [[Do\|do]]
14	+	- [[Downto\|downto]]
15	+	- [[Else\|else]]
16	+	- [[End\|end]]
17	+	- [[File\|file]]
18	+	- [[For\|for]]
19	+	- [[Function\|function]]
20	+	- [[Goto\|goto]]
21	+	- [[If\|if]]
22	+	- [[In\|in]]
23	+	- [[Label\|label]]
24	+	- [[Mod\|mod]]
25	+	- [[Nil\|nil]]
26	+	- [[Not\|not]]
27	+	- [[Of\|of]]
28	+	- [[Or\|or]]
29	+	- [[Packed\|packed]]
30	+	- [[Procedure\|procedure]]
31	+	- [[Program\|program]]
32	+	- [[Record\|record]]
33	+	- [[Repeat\|repeat]]
34	+	- [[Set\|set]]
35	+	- [[Then\|then]]
36	+	- [[To\|to]]
37	+	- [[Type\|type]]
38	+	- [[Until\|until]]
39	+	- [[Var\|var]]
40	+	- [[While\|while]]
41	+	- [[With\|with]]
42	+
43	+	## Symbols
44	+
45	+	The following symbols (which the standard refers to as special-symbols) are also part of the language:
46	+
47	+	- \+ ([[Plus\|plus]])
48	+
49	+	- \- ([[Minus\|minus]])
50	+
51	+	- * ([[*\|asterisk]])
52	+
53	+	- / ([[Slash\|slash]])
54	+
55	+	- = ([[Equal\|equal]])
56	+
57	+	- \< ([[Less than\|less than]])
58	+
59	+	- \> ([[Greater than\|greater than]])
60	+
61	+	- \[
62	+
63	+	- \]
64	+
65	+	- . ([[period]])
66	+
67	+	- , ([[Comma\|comma]])
68	+
69	+	-
70	+	([[Colon\|colon]])
71	+
72	+	- ; ([[;\|semicolon]])
73	+
74	+	- ↑
75	+
76	+	- (
77	+
78	+	- )
79	+
80	+	- \<\> ([[Not equal\|not equal]])
81	+
82	+	- \<=
83	+
84	+	- \>=
85	+
86	+	-
87	+	= (named [[Becomes\|becomes]])
88	+
89	+	- ..
90	+
91	+	## Functions
92	+
93	+	All of the functions defined by Standard Pascal are implemented in Free Pascal in the [[System unit]] of the standard [[RTL\|Runtime Library]].
94	+
95	+	### Arithmetic Functions
96	+
97	+	\| Function \| Description \|
98	+	\|----\|----\|
99	+	\| abs(x) \| Calculate the absolute value of x \|
100	+	\| arctan(x) \| arctan returns the arctangent of x, which can be any Real type. The resulting angle is in radial units. \|
101	+	\| cos(x) \| Calculate cosine of angle x ([[Radian\|radians]]) \|
102	+	\| exp(x) \| Exp returns the exponent of x, i.e. the number e to the power x \|
103	+	\| ln(x) \| returns the natural logarithm of the Real parameter x. x must be positive. \|
104	+	\| sin(x) \| Calculate the sine of angle x (radians) \|
105	+	\| sqr(x) \| Calculate the square of x \|
106	+	\| sqrt(x) \| Calculate the square root of x. x must be positive. \|
107	+	\| \| \|
108	+
109	+	### Transfer Functions
110	+
111	+	\| Function \| Description \|
112	+	\|----\|----\|
113	+	\| [[Round\|round]](x) \| Round floating point value to nearest integer number and return as integer. \|
114	+	\| [[Trunc\|trunc]](x) \| Truncate floating point x value and return as integer. \|
115	+	\| \| \|
116	+
117	+	### Ordinal Functions
118	+
119	+	\| Function \| Description \|
120	+	\|----\|----\|
121	+	\| [[Chr\|chr]](x) \| Convert byte value to a character value \|
122	+	\| [[Ord\|ord]](x) \| Return ordinal value of an ordinal type. \|
123	+	\| [[Pred\|pred]](x) \| Return previous element for an ordinal type. \|
124	+	\| [[Succ\|succ]](x) \| Return next element of ordinal type. \|
125	+	\| \| \|
126	+
127	+	### Boolean Functions
128	+
129	+	\| Function \| Description \|
130	+	\|----\|----\|
131	+	\| [[EOLN and EOF\|eof]](f) \| Check for end of file f \|
132	+	\| [[EOLN and EOF\|eoln]](f) \| Check for end of line on textfile f \|
133	+	\| [[Odd\|odd]](x) \| Is a x odd or even ? \|
134	+	\| \| \|
135	+
136	+	## Procedures
137	+
138	+	Procedures defined by Standard Pascal are implemented in Free Pascal in the [[System unit]] of the standard [[RTL\|Runtime Library]].
139	+
140	+	### File handling procedures
141	+
142	+	\| Procedure \| Description \|
143	+	\|----\|----\|
144	+	\| [[Get\|get]](f) \| \|
145	+	\| [[Page\|page]]() \| \|
146	+	\| [[Put\|put]](f) \| \|
147	+	\| [[Read\|read]] \| Read from a text file or stdin into a [[Variable\|variable]] \|
148	+	\| [[Read\|readln]] \| Read from a text file into variable and goto next line \|
149	+	\| [[Reset\|reset]](f) \| Open file for reading \|
150	+	\| [[Rewrite\|rewrite]](f) \| Open file for writing \|
151	+	\| [[Write\|write]] \| Write variable or literal string to a text file or stdout \|
152	+	\| [[Write\|writeln]] \| Write variable or literal string to a text file or stdout and append newline \|
153	+	\| \| \|
154	+
155	+	### Dynamic allocation procedures
156	+
157	+	\| Procedure \| Description \|
158	+	\|----\|----\|
159	+	\| [[Dispose\|dispose]](q) \| Release the memory pointed to by q, which was allocated with a call to New. \|
160	+	\| dispose(q,k1...kn) \| \|
161	+	\| [[New\|new]](p) \| New allocates a new instance of the type pointed to by p, and puts the address in p. \|
162	+	\| new(p,c1...cn) \| \|
163	+	\| \| \|
164	+
165	+	### Transfer procedures
166	+
167	+	\| Procedure \| Description \|
168	+	\|-----------\|-----------------------------------------\|
169	+	\| pack() \| Create packed array from normal array \|
170	+	\| unpack() \| Create unpacked array from packed array \|
171	+	\| \| \|
172	+
173	+	## Extensions
174	+
175	+	There are additional keywords which are not technically part of the Standard Pascal language but are used by [[FPC]] either for additional functionality such as for implementing objects, compatibility with the error recovery concepts exposed by C++, or to provide compatibility with [[Borland Pascal]] and earlier Pascal compilers. These keywords include:
176	+
177	+
178	+	[[Implementation\|implementation]] · [[Finally\|finally]] · [[Try\|try]] · [[Unit\|unit]].
179	+
180	+	## Types
181	+
182	+	There are the standard [[Type\|types]]:
183	+
184	+	[[Integer\|integer]] · [[Smallint\|smallint]] · [[Longint\|longint]] · [[Real\|real]] · [[Boolean\|boolean]] · [[String\|string]] · [[Char\|char]] · [[Byte\|byte]]
185	+
186	+	## Modes supported by Free Pascal
187	+
188	+	Free Pascal supports ISO 7185 Standard Pascal with the [[Compiler Mode\|compiler mode]] [[Command-line interface\|command line]] option -Miso or with the [[Source code\|source code]] [[Compiler directive\|compiler directive]] [[Mode iso\|{$mode ISO}]]. Support of ISO 7185 started with version 3.0.0. It is planned to have a mode support ISO/IEC 10206 [[Extended Pascal]] in future versions of Free Pascal.
189	+
190	+	## External links
191	+
192	+	- [Standard Pascal](http://www.standardpascal.org), reference information about the ANSI ISO 7185 standard.
193	+	- [ISO 7185:1990](http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=13802), official normative version of the Pascal standard.
194	+	- [ISO/IEC 10206:1991](http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=18237): Extended Pascal standard
195	+
196	+	---
197	+	From the Free Pascal wiki, page "Standard Pascal", as it stood on 2023-09-11 after a change by Chernov, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).

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