harlowe:datatype

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All of the datatypes are as follows. | All of the datatypes are as follows. | ||

- | | Value | Data type| | + | | **Value** | **Data type**| |

- | |--- | + | |

| ''%%number%%'', ''%%num%%'' | [[harlowe:number|Numbers]]| | | ''%%number%%'', ''%%num%%'' | [[harlowe:number|Numbers]]| | ||

| ''%%string%%'', ''%%str%%'' | [[harlowe:string|Strings]]| | | ''%%string%%'', ''%%str%%'' | [[harlowe:string|Strings]]| | ||

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Note that data that can't be stored in a variable doesn't have a corresponding datatype name, because you won't need to compare things to it. | Note that data that can't be stored in a variable doesn't have a corresponding datatype name, because you won't need to compare things to it. | ||

- | Additionally, along with the `is a` operator, there is a `matches` operator which is useful when you're dealing with data structures like [[harlowe:array|arrays]] or [[harlowe:datamap|datamaps]]. `$pos is a array` checks if $pos is an array, but that may not be precise enough for you. `$pos matches (a: number, number)` checks to see if $pos is an array containing only two numbers in a row. A data structure with datatype names in various positions inside it is called a **pattern**, and `matches` is used to compare data values and patterns. | + | Additionally, along with the ''%%is a%%'' operator, there is a ''%%matches%%'' operator which is useful when you're dealing with data structures like [[harlowe:array|arrays]] or [[harlowe:datamap|datamaps]]. ''%%$pos is a array%%'' checks if $pos is an array, but that may not be precise enough for you. ''%%$pos matches (a: number, number)%%'' checks to see if $pos is an array containing only two numbers in a row. A data structure with datatype names in various positions inside it is called a **pattern**, and ''%%matches%%'' is used to compare data values and patterns. |

Some more pattern-matching examples: | Some more pattern-matching examples: | ||

- | * `(datamap:'a',2,'b',4) matches (datamap:'b',num,'a',num))` is true. | + | * ''%%(datamap:'a',2,'b',4) matches (datamap:'b',num,'a',num))%%'' is true. |

- | * `(a: 2, 3, 4) matches (a: 2, num, num)` is true. (Patterns can have exact values in them, which must be equal in the matching data). | + | * ''%%(a: 2, 3, 4) matches (a: 2, num, num)%%'' is true. (Patterns can have exact values in them, which must be equal in the matching data). |

- | * `(a: (a: 2), (a: 4)) matches (a: (a: num), (a: num))` is true. | + | * ''%%(a: (a: 2), (a: 4)) matches (a: (a: num), (a: num))%%'' is true. |

To summarise, the two datatype-checking operators are: | To summarise, the two datatype-checking operators are: | ||

- | | Operator | Purpose | Example| | + | |**Operator** | **Purpose** | **Example**| |

- | |--- | + | |

| ''%%matches%%'' | Evaluates to [[harlowe:boolean|boolean]] true if the data on the left matches the pattern on the right. | ''%%(a:2,3) matches (a: num, num)%%''| | | ''%%matches%%'' | Evaluates to [[harlowe:boolean|boolean]] true if the data on the left matches the pattern on the right. | ''%%(a:2,3) matches (a: num, num)%%''| | ||

| ''%%is a%%'', ''%%is an%%'' | Similar to matches, but requires the right side to be just a type name. | ''%%(a:2,3) is an array%%'', ''%%4.1 is a number%%''| | | ''%%is a%%'', ''%%is an%%'' | Similar to matches, but requires the right side to be just a type name. | ''%%(a:2,3) is an array%%'', ''%%4.1 is a number%%''| |

harlowe/datatype.txt · Last modified: 2019/04/16 04:03 by l

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