period: what changed
Revision 0 to 1. Removed lines have a minus sign; added lines have a plus sign.
Title: period
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| 1 | + | ## radix mark | |
| 2 | + | ||
| 3 | + | [[Pascal]] uses the `.` (dot) to separate the integer and fractional part in literal decimal integers. | |
| 4 | + | ||
| 5 | + | ``` pascal | |
| 6 | + | myReal := 6.28318 | |
| 7 | + | ``` | |
| 8 | + | ||
| 9 | + | At least one digit in front of the period is mandatory. A `0` integer part must not be omitted. | |
| 10 | + | ||
| 11 | + | Numbers noted in a non-decimal base can not be noted in that way. E. g. the numeric value “a half” can not be written as `%0.1` ([[Percent sign|%]] being the prefix marking [[Binary numeral system|binary numbers]]). | |
| 12 | + | ||
| 13 | + | ## identifier scope selector | |
| 14 | + | ||
| 15 | + | For structured data types the dot separates the data structure identifier from its individual components, i. e. methods or data fields. | |
| 16 | + | ||
| 17 | + | ``` pascal | |
| 18 | + | program recordDemo(input, output, stderr); | |
| 19 | + | ||
| 20 | + | uses | |
| 21 | + | Linux; | |
| 22 | + | ||
| 23 | + | var | |
| 24 | + | info: TSysInfo; | |
| 25 | + | begin | |
| 26 | + | if sysInfo(@info) <> 0 then | |
| 27 | + | begin | |
| 28 | + | halt(1); | |
| 29 | + | end; | |
| 30 | + | ||
| 31 | + | writeLn('uptime: ', info.uptime, ' seconds'); | |
| 32 | + | ||
| 33 | + | with info do | |
| 34 | + | begin | |
| 35 | + | writeLn('total free: ', freeram, ' bytes'); | |
| 36 | + | end; | |
| 37 | + | end. | |
| 38 | + | ``` | |
| 39 | + | ||
| 40 | + | ## range | |
| 41 | + | ||
| 42 | + | Two consecutive dots `..` let you specify an ordinal [[subrange types|type sub-range]]. | |
| 43 | + | ||
| 44 | + | ``` pascal | |
| 45 | + | type | |
| 46 | + | signumCodomain = -1..1; | |
| 47 | + | ``` | |
| 48 | + | ||
| 49 | + | This is the same as [`math.TValueSign`](https://www.freepascal.org/docs-html/rtl/math/tvaluesign.html). | |
| 50 | + | ||
| 51 | + | ## module end | |
| 52 | + | ||
| 53 | + | The main block of any module, i. e. [[Program|program]], [[Unit|unit]] or [[Library|library]], has to be closed with an [[End|end]] “dot”: | |
| 54 | + | ||
| 55 | + | ``` pascal | |
| 56 | + | program hiWorld(input, output, stderr); | |
| 57 | + | ||
| 58 | + | begin | |
| 59 | + | writeLn('Hi world!'); | |
| 60 | + | end. | |
| 61 | + | ``` | |
| 62 | + | ||
| 63 | + | It can be seen as an adoption of natural (written) languages, where a full stop marks an end of a sentence. | |
| 64 | + | ||
| 65 | + | Anything else after the final `end.`, assuming syntactical correctness, will be ignored by the [[Compiler|compiler]]. | |
| 66 | + | ||
| 67 | + | ## namespaces | |
| 68 | + | ||
| 69 | + | [[Unit]] names containing dots create [[Namespaces|namespaces]]. | |
| 70 | + | ||
| 71 | + | ## ASCII value | |
| 72 | + | ||
| 73 | + | In [[ASCII]], the character code decimal `46` (or [[Hexadecimal|hexadecimal]] `2E`) is defined to be `.` (full stop). | |
| 74 | + | ||
| 75 | + | --- | |
| 76 | + | *From the Free Pascal wiki, page "period", as it stood on 2020-07-09 after a change by Kai Burghardt, 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).* | |
| 77 | + | Category: Code |