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Enhance array functions.

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This commit is contained in:
Stephen Chung
2020-10-14 21:27:31 +08:00
parent 3df8d6c398
commit e0c39edff4
3 changed files with 181 additions and 49 deletions
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83
doc/src/language/arrays.md
View File

@@ -30,32 +30,33 @@ Built-in Functions
The following methods (mostly defined in the [`BasicArrayPackage`][packages] but excluded if using a [raw `Engine`]) operate on arrays:
| Function | Parameter(s) | Description |
| ------------------------- | --------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `push` | element to insert | inserts an element at the end |
| `append` | array to append | concatenates the second array to the end of the first |
| `+=` operator | 1) array<br/>2) element to insert (not another array) | inserts an element at the end |
| `+=` operator | 1) array<br/>2) array to append | concatenates the second array to the end of the first |
| `+` operator | 1) first array<br/>2) second array | concatenates the first array with the second |
| `insert` | 1) element to insert<br/>2) position, beginning if < 0, end if > length | inserts an element at a certain index |
| `pop` | _none_ | removes the last element and returns it ([`()`] if empty) |
| `shift` | _none_ | removes the first element and returns it ([`()`] if empty) |
| `extract` | 1) start position, beginning if < 0, end if > length,<br/>2) number of items to extract, none if < 0 _(optional)_ | extracts a portion of the array into a new array |
| `remove` | index | removes an element at a particular index and returns it ([`()`] if the index is not valid) |
| `reverse` | _none_ | reverses the array |
| `len` method and property | _none_ | returns the number of elements |
| `pad` | 1) target length<br/>2) element to pad | pads the array with an element to at least a specified length |
| `clear` | _none_ | empties the array |
| `truncate` | target length | cuts off the array at exactly a specified length (discarding all subsequent elements) |
| `chop` | target length | cuts off the head of the array, leaving the tail at exactly a specified length |
| `splice` | 1) start position, beginning if < 0, end if > length,<br/>2) number of items to remove, none if < 0,<br/>3) array to insert | replaces a portion of the array with another (not necessarily of the same length as the replaced portion) |
| `filter` | [function pointer] to predicate (can be a [closure]) | constructs a new array with all items that returns `true` when called with the predicate function:<br/>1st parameter: array item,<br/>2nd parameter: offset index _(optional)_ |
| `map` | [function pointer] to conversion function (can be a [closure]) | constructs a new array with all items mapped to the result of applying the conversion function:<br/>1st parameter: array item,<br/>2nd parameter: offset index _(optional)_ |
| `reduce` | [function pointer] to accumulator function (can be a [closure]) | reduces the array into a single value via the accumulator function:<br/>1st parameter: accumulated value ([`()`] initially),<br/>2nd parameter: array item,<br/>3rd parameter: offset index _(optional)_ |
| `reduce_rev` | [function pointer] to accumulator function (can be a [closure]) | reduces the array (in reverse order) into a single value via the accumulator function:<br/>1st parameter: accumulated value ([`()`] initially),<br/>2nd parameter: array item,<br/>3rd parameter: offset index _(optional)_ |
| `some` | [function pointer] to predicate (can be a [closure]) | returns `true` if any item returns `true` when called with the predicate function:<br/>1st parameter: array item,<br/>2nd parameter: offset index _(optional)_ |
| `all` | [function pointer] to predicate (can be a [closure]) | returns `true` if all item returns `true` when called with the predicate function:<br/>1st parameter: array item,<br/>2nd parameter: offset index _(optional)_ |
| `sort` | [function pointer] to a comparison function (can be a [closure]) | sorts the array with a comparison function:<br/>1st parameter: first item,<br/>2nd parameter: second item,<br/>return value: `INT` < 0 if first < second, > 0 if first > second, 0 if first == second |
| Function | Parameter(s) | Description |
| ------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `push` | element to insert | inserts an element at the end |
| `append` | array to append | concatenates the second array to the end of the first |
| `+=` operator | 1) array<br/>2) element to insert (not another array) | inserts an element at the end |
| `+=` operator | 1) array<br/>2) array to append | concatenates the second array to the end of the first |
| `+` operator | 1) first array<br/>2) second array | concatenates the first array with the second |
| `insert` | 1) element to insert<br/>2) position, beginning if < 0, end if > length | inserts an element at a certain index |
| `pop` | _none_ | removes the last element and returns it ([`()`] if empty) |
| `shift` | _none_ | removes the first element and returns it ([`()`] if empty) |
| `extract` | 1) start position, beginning if < 0, end if > length,<br/>2) _(optional)_ number of items to extract, none if < 0 | extracts a portion of the array into a new array |
| `remove` | index | removes an element at a particular index and returns it ([`()`] if the index is not valid) |
| `reverse` | _none_ | reverses the array |
| `len` method and property | _none_ | returns the number of elements |
| `pad` | 1) target length<br/>2) element to pad | pads the array with an element to at least a specified length |
| `clear` | _none_ | empties the array |
| `truncate` | target length | cuts off the array at exactly a specified length (discarding all subsequent elements) |
| `chop` | target length | cuts off the head of the array, leaving the tail at exactly a specified length |
| `splice` | 1) start position, beginning if < 0, end if > length,<br/>2) number of items to remove, none if < 0,<br/>3) array to insert | replaces a portion of the array with another (not necessarily of the same length as the replaced portion) |
| `filter` | [function pointer] to predicate (usually a [closure]) | constructs a new array with all items that returns `true` when called with the predicate function:<br/>1st parameter: array item,<br/>2nd parameter: _(optional)_ offset index |
| `map` | [function pointer] to conversion function (usually a [closure]) | constructs a new array with all items mapped to the result of applying the conversion function:<br/>1st parameter: array item,<br/>2nd parameter: _(optional)_ offset index |
| `reduce` | 1) [function pointer] to accumulator function (usually a [closure]),<br/>2) _(optional)_ [function pointer] to function (usually a [closure]) that provides the initial value | reduces the array into a single value via the accumulator function:<br/>1st parameter: accumulated value ([`()`] initially),<br/>2nd parameter: array item,<br/>3rd parameter: _(optional)_ offset index |
| `reduce_rev` | 1) [function pointer] to accumulator function (usually a [closure]),<br/>2) _(optional)_ [function pointer] to function (usually a [closure]) that provides the initial value | reduces the array (in reverse order) into a single value via the accumulator function:<br/>1st parameter: accumulated value ([`()`] initially),<br/>2nd parameter: array item,<br/>3rd parameter: _(optional)_ offset index |
| `some` | [function pointer] to predicate (usually a [closure]) | returns `true` if any item returns `true` when called with the predicate function:<br/>1st parameter: array item,<br/>2nd parameter: _(optional)_ offset index |
| `none` | [function pointer] to predicate (usually a [closure]) | returns `true` if no item returns `true` when called with the predicate function:<br/>1st parameter: array item,<br/>2nd parameter: _(optional)_ offset index |
| `all` | [function pointer] to predicate (usually a [closure]) | returns `true` if all items return `true` when called with the predicate function:<br/>1st parameter: array item,<br/>2nd parameter: _(optional)_ offset index |
| `sort` | [function pointer] to a comparison function (usually a [closure]) | sorts the array with a comparison function:<br/>1st parameter: first item,<br/>2nd parameter: second item,<br/>return value: `INT` < 0 if first < second, > 0 if first > second, 0 if first == second |
Use Custom Types With Arrays
@@ -156,21 +157,29 @@ a.filter(|v| v > 50); // returns [123, 99]
a.filter(|v, i| i == 1); // returns [123]
a.reduce(|sum, v| {
// Detect the initial value of '()'
if sum.type_of() == "()" { v } else { sum + v }
// Use a closure to provide the initial value
a.reduce(|sum, v| sum + v, || 0) == 264;
// Detect the initial value of '()'
a.reduce(
|sum, v| if sum.type_of() == "()" { v } else { sum + v }
) == 264;
a.reduce(|sum, v, i| {
// Detect the initial value via index
a.reduce(|sum, v, i|
if i == 0 { v } else { sum + v }
) == 264;
a.reduce_rev(|sum, v| {
// Detect the initial value of '()'
if sum.type_of() == "()" { v } else { sum + v }
// Use a closure to provide the initial value
a.reduce_rev(|sum, v| sum + v, || 0) == 264;
// Detect the initial value of '()'
a.reduce_rev(
|sum, v| if sum.type_of() == "()" { v } else { sum + v }
) == 264;
a.reduce_rev(|sum, v, i| {
// Detect the initial value via index
a.reduce_rev(|sum, v, i|
if i == 2 { v } else { sum + v }
) == 264;
@@ -178,6 +187,10 @@ a.some(|v| v > 50); // returns true
a.some(|v, i| v < i); // returns false
a.none(|v| v != 0); // returns false
a.none(|v, i| v == i); // returns true
a.all(|v| v > 50); // returns false
a.all(|v, i| v > i); // returns true
@@ -186,5 +199,5 @@ a.splice(1, 1, [1, 3, 2]); // a == [42, 1, 3, 2, 99]
a.extract(1, 3); // returns [1, 3, 2]
a.sort(|x, y| x - y); // a == [1, 2, 3, 42, 99]
a.sort(|x, y| x - y); // a == [1, 2, 3, 42, 99]
```

28
doc/src/language/string-fn.md
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@@ -6,20 +6,20 @@ Built-in String Functions
The following standard methods (mostly defined in the [`MoreStringPackage`][packages] but excluded if
using a [raw `Engine`]) operate on [strings]:
| Function | Parameter(s) | Description |
| ------------------------- | --------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- |
| `len` method and property | _none_ | returns the number of characters (not number of bytes) in the string |
| `pad` | 1) character to pad<br/>2) target length | pads the string with an character to at least a specified length |
| `+=` operator, `append` | character/string to append | Adds a character or a string to the end of another string |
| `clear` | _none_ | empties the string |
| `truncate` | target length | cuts off the string at exactly a specified number of characters |
| `contains` | character/sub-string to search for | checks if a certain character or sub-string occurs in the string |
| `index_of` | 1) character/sub-string to search for<br/>2) start index _(optional)_ | returns the index that a certain character or sub-string occurs in the string, or -1 if not found |
| `sub_string` | 1) start index<br/>2) length _(optional)_ | extracts a sub-string (to the end of the string if length is not specified) |
| `split` | delimiter character/string | splits the string by the specified delimiter, returning an [array] of string segments; not available under [`no_index`] |
| `crop` | 1) start index<br/>2) length _(optional)_ | retains only a portion of the string (to the end of the string if length is not specified) |
| `replace` | 1) target character/sub-string<br/>2) replacement character/string | replaces a sub-string with another |
| `trim` | _none_ | trims the string of whitespace at the beginning and end |
| Function | Parameter(s) | Description |
| ------------------------- | ------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- |
| `len` method and property | _none_ | returns the number of characters (not number of bytes) in the string |
| `pad` | 1) character to pad<br/>2) target length | pads the string with an character to at least a specified length |
| `+=` operator, `append` | character/string to append | Adds a character or a string to the end of another string |
| `clear` | _none_ | empties the string |
| `truncate` | target length | cuts off the string at exactly a specified number of characters |
| `contains` | character/sub-string to search for | checks if a certain character or sub-string occurs in the string |
| `index_of` | 1) character/sub-string to search for<br/>2) _(optional)_ start index | returns the index that a certain character or sub-string occurs in the string, or -1 if not found |
| `sub_string` | 1) start index<br/>2) _(optional)_ number of characters to extract, none if < 0 | extracts a sub-string (to the end of the string if length is not specified) |
| `split` | delimiter character/string | splits the string by the specified delimiter, returning an [array] of string segments; not available under [`no_index`] |
| `crop` | 1) start index<br/>2) _(optional)_ number of characters to retain, none if < 0 | retains only a portion of the string |
| `replace` | 1) target character/sub-string<br/>2) replacement character/string | replaces a sub-string with another |
| `trim` | _none_ | trims the string of whitespace at the beginning and end |
Examples
--------