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A '''quad name''' or ''system name'' is a general term for built-ins denoted by a name beginning with the quad character, <source lang=apl inline>⎕</source>. The term only used when explicitly needing to cover all syntactic classes of such built-ins; constants, variables, objects, functions and operators. It is common to call these ''system constants'', ''system variables'', etc., although the term ''system function'' is often used as a synonym for ''quad name''. Quad names are used for features that abide by the normal syntax, but are not part of the core language. <source lang=apl inline>⎕</source> by itself (standard output/evaluated input) and <source lang=apl inline>⍞</source> (message output/standard input) are often included in the quad name category. | A '''quad name''' or ''system name'' is a general term for built-ins denoted by a name beginning with the quad character, <source lang=apl inline>⎕</source>. The term only used when explicitly needing to cover all syntactic classes of such built-ins; constants, variables, objects, functions and operators. It is common to call these ''system constants'', ''system variables'', etc., although the term ''system function'' is often used as a synonym for ''quad name''. Quad names are used for features that abide by the normal syntax, but are not part of the core language. <source lang=apl inline>⎕</source> by itself (standard output/evaluated input) and <source lang=apl inline>⍞</source> (message output/standard input) are often included in the quad name category. | ||
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* System variables are used to alter the behaviour of the language. For example the number of significant digits displayed can be controlled by setting the [[print precision]] (<source lang=apl inline>⎕PP</source>). | * System variables are used to alter the behaviour of the language. For example the number of significant digits displayed can be controlled by setting the [[print precision]] (<source lang=apl inline>⎕PP</source>). | ||
* System objects are references to namespaces, in particular the session object (<source lang=apl inline>⎕SE</source>). | * System objects are references to namespaces, in particular the session object (<source lang=apl inline>⎕SE</source>). | ||
* System functions are various utility functions, like | * System functions are various utility functions, like <source lang=apl inline>⎕FX</source> to define ("FiX") a function under program control. | ||
* System operators only occur in [[Dyalog APL]] and are used for things like text search and replace (<source lang=apl inline>⎕S</source> and <source lang=apl inline>⎕R</source>). | * System operators only occur in [[Dyalog APL]] and are used for things like text search and replace (<source lang=apl inline>⎕S</source> and <source lang=apl inline>⎕R</source>). | ||
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* [http://help.dyalog.com/latest/#Language/System%20Functions/Summary%20Tables/Introduction.htm Dyalog] | * [http://help.dyalog.com/latest/#Language/System%20Functions/Summary%20Tables/Introduction.htm Dyalog] | ||
* [http://microapl.com/apl_help/ch_020_070.htm APLX] | * [http://microapl.com/apl_help/ch_020_070.htm APLX] | ||
{{APL features}} | {{APL features}}[[Category:APL syntax]] |