diff options
| -rw-r--r-- | runtime/doc/eval.txt | 149 |
1 files changed, 136 insertions, 13 deletions
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt index 70f970ffef..2efd7077d9 100644 --- a/runtime/doc/eval.txt +++ b/runtime/doc/eval.txt @@ -34,7 +34,7 @@ Funcref A reference to a function |Funcref|. like a Partial. Example: function("Callback", [arg], myDict) -List An ordered sequence of items |List|. +List An ordered sequence of items, see |List| for details. Example: [1, 2, ['a', 'b']] Dictionary An associative, unordered array: Each entry has a key and a @@ -43,7 +43,8 @@ Dictionary An associative, unordered array: Each entry has a key and a {'blue': "#0000ff", 'red': "#ff0000"} #{blue: "#0000ff", red: "#ff0000"} -Blob Binary Large Object. Stores any sequence of bytes. *Blob* +Blob Binary Large Object. Stores any sequence of bytes. See |Blob| + for details. Example: 0zFF00ED015DAF 0z is an empty Blob. @@ -599,7 +600,120 @@ Functions that can be used with a Dictionary: > :call map(dict, '">> " . v:val') " prepend ">> " to each item -1.5 More about variables ~ +1.5 Blobs ~ + *blob* *Blob* *Blobs* *E978* +A Blob mostly behaves like a |List| of numbers, where the numbers have an +8-bit value, from 0 to 255. + + +Blob creation ~ + +A Blob can be created with a |blob-literal|: > + :let b = 0zFF00ED015DAF + +A blob can be read from a file with |readfile()| passing the {type} argument +set to "B", for example: > + :let b = readfile('image.png', 'B') + + +Blob index ~ + *blob-index* *E979* +A byte in the Blob can be accessed by putting the index in square brackets +after the Blob. Indexes are zero-based, thus the first byte has index zero. > + :let myblob = 0z00112233 + :let byte = myblob[0] " get the first byte: 0x00 + :let byte = myblob[2] " get the third byte: 0x22 + +A negative index is counted from the end. Index -1 refers to the last byte in +the Blob, -2 to the last but one byte, etc. > + :let last = myblob[-1] " get the last byte: 0x33 + +To avoid an error for an invalid index use the |get()| function. When an item +is not available it returns -1 or the default value you specify: > + :echo get(myblob, idx) + :echo get(myblob, idx, 999) + + +Blob concatenation ~ + +Two blobs can be concatenated with the "+" operator: > + :let longblob = myblob + 0z4455 + :let myblob += 0z6677 + +To change a blob in-place see |blob-modification| below. + + +Part of a blob ~ + +A part of the Blob can be obtained by specifying the first and last index, +separated by a colon in square brackets: > + :let myblob = 0z00112233 + :let shortblob = myblob[2:-1] " get 0z2233 + +Omitting the first index is similar to zero. Omitting the last index is +similar to -1. > + :let endblob = myblob[2:] " from item 2 to the end: 0z2233 + :let shortblob = myblob[2:2] " Blob with one byte: 0z22 + :let otherblob = myblob[:] " make a copy of the Blob + +If the first index is beyond the last byte of the Blob or the second byte is +before the first byte, the result is an empty Blob. There is no error +message. + +If the second index is equal to or greater than the length of the Blob the +length minus one is used: > + :echo myblob[2:8] " result: 0z2233 + + +Blob modification ~ + *blob-modification* +To change a specific byte of a blob use |:let| this way: > + :let blob[4] = 0x44 + +When the index is just one beyond the end of the Blob, it is appended. Any +higher index is an error. + +To change a sequence of bytes the [:] notation can be used: > + let blob[1:3] = 0z445566 +The length of the replaced bytes must be exactly the same as the value +provided. *E972* + +To change part of a blob you can specify the first and last byte to be +modified. The value must at least have the number of bytes in the range: > + :let blob[3:5] = [3, 4, 5] + +You can also use the functions |add()|, |remove()| and |insert()|. + + +Blob identity ~ + +Blobs can be compared for equality: > + if blob == 0z001122 +And for equal identity: > + if blob is otherblob +< *blob-identity* *E977* +When variable "aa" is a Blob and you assign it to another variable "bb", both +variables refer to the same Blob. Then the "is" operator returns true. + +When making a copy using [:] or |copy()| the values are the same, but the +identity is different: > + :let blob = 0z112233 + :let blob2 = blob + :echo blob == blob2 +< 1 > + :echo blob is blob2 +< 1 > + :let blob3 = blob[:] + :echo blob == blob3 +< 1 > + :echo blob is blob3 +< 0 + +Making a copy of a Blob is done with the |copy()| function. Using [:] also +works, as explained above. + + +1.6 More about variables ~ *more-variables* If you need to know the type of a variable or expression, use the |type()| function. @@ -1191,7 +1305,7 @@ encodings. Use "\u00ff" to store character 255 correctly as UTF-8. Note that "\000" and "\x00" force the end of the string. -blob-literal *blob-literal* *E973* *E977* *E978* +blob-literal *blob-literal* *E973* ------------ Hexadecimal starting with 0z or 0Z, with an arbitrary number of bytes. @@ -2124,7 +2238,7 @@ USAGE RESULT DESCRIPTION ~ abs({expr}) Float or Number absolute value of {expr} acos({expr}) Float arc cosine of {expr} -add({list}, {item}) List append {item} to |List| {list} +add({object}, {item}) List/Blob append {item} to {object} and({expr}, {expr}) Number bitwise AND api_info() Dict api metadata append({lnum}, {string}) Number append {string} below line {lnum} @@ -2668,13 +2782,14 @@ acos({expr}) *acos()* Can also be used as a |method|: > Compute()->acos() -add({list}, {expr}) *add()* - Append the item {expr} to |List| {list}. Returns the - resulting |List|. Examples: > +add({object}, {expr}) *add()* + Append the item {expr} to |List| or |Blob| {object}. Returns + the resulting |List| or |Blob|. Examples: > :let alist = add([1, 2, 3], item) :call add(mylist, "woodstock") < Note that when {expr} is a |List| it is appended as a single item. Use |extend()| to concatenate |Lists|. + When {object} is a |Blob| then {expr} must be a number. Use |insert()| to add an item at another position. Can also be used as a |method|: > @@ -3661,9 +3776,13 @@ diff_hlID({lnum}, {col}) *diff_hlID()* empty({expr}) *empty()* Return the Number 1 if {expr} is empty, zero otherwise. - A |List| or |Dictionary| is empty when it does not have any - items. A Number is empty when its value is zero. Special - variable is empty when it is |v:false| or |v:null|. + - A |List| or |Dictionary| is empty when it does not have any + items. + - A |String| is empty when its length is zero. + - A |Number| and |Float| are empty when their value is zero. + - |v:false| and |v:null| are empty, |v:true| is not. + - A |Blob| is empty when its length is zero. + Can also be used as a |method|: > mylist->empty() @@ -4383,6 +4502,10 @@ get({list}, {idx} [, {default}]) *get()* omitted. Can also be used as a |method|: > mylist->get(idx) +get({blob}, {idx} [, {default}]) + Get byte {idx} from |Blob| {blob}. When this byte is not + available return {default}. Return -1 when {default} is + omitted. get({dict}, {key} [, {default}]) Get item with key {key} from |Dictionary| {dict}. When this item is not available return {default}. Return zero when @@ -5573,10 +5696,10 @@ index({object}, {expr} [, {start} [, {ic}]]) *index()* If {object} is a |List| return the lowest index where the item has a value equal to {expr}. There is no automatic conversion, so the String "4" is different from the Number 4. - And the number 4 is different from the Float 4.0. The value + And the Number 4 is different from the Float 4.0. The value of 'ignorecase' is not used here, case always matters. - If {object} is |Blob| return the lowest index where the byte + If {object} is a |Blob| return the lowest index where the byte value is equal to {expr}. If {start} is given then start looking at the item with index |