tango.text.Text

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_Text is a class for storing and manipulating Unicode characters.

_Text maintains a current "selection", controlled via the mark(), select() and selectPrior() methods. Each of append(), prepend(), replace() and remove() operate with respect to the selection. The select() methods operate with respect to the current selection also, providing a means of iterating across matched patterns. To set a selection across the entire content, use the mark() method with no arguments.

Indexes and lengths of content always count code units, not code points. This is similar to traditional ascii string handling, yet indexing is rarely used in practice due to the selection idiom: substring indexing is generally implied as opposed to manipulated directly. This allows for a more streamlined model with regard to surrogates.

Strings support a range of functionality, from insert and removal to utf encoding and decoding. There is also an immutable subset called TextView, intended to simplify life in a multi-threaded environment. However, TextView must expose the raw content as needed and thus immutability depends to an extent upon so-called "honour" of a callee. D does not enable immutability enforcement at this time, but this class will be modified to support such a feature when it arrives - via the slice() method.

The class is templated for use with char[], wchar[], and dchar[], and should migrate across encodings seamlessly. In particular, all functions in tango.text.Util are compatible with _Text content in any of the supported encodings. In future, this class will become the principal gateway to the extensive ICU unicode library.

Note that several common text operations can be constructed through combining tango.text._Text with tango.text.Util e.g. lines of text can be processed thusly:

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auto source = new Text!(char)("one\ntwo\nthree");

foreach (line; Util.lines(source.slice))
         // do something with line

Substituting patterns within text can be implemented simply and rather efficiently:

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auto dst = new Text!(char);

foreach (element; Util.patterns ("all cows eat grass", "eat", "chew"))
         dst.append (element);

Speaking a bit like Yoda might be accomplished as follows:

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auto dst = new Text!(char);

foreach (element; Util.delims ("all cows eat grass", " "))
         dst.prepend (element);

Below is an overview of the API and class hierarchy:

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class Text(T) : TextView!(T)
{
        // set or reset the content
        Text set (T[] chars, bool mutable=true);
        Text set (TextView other, bool mutable=true);

        // retreive currently selected text
        T[] selection ();

        // get the index and length of the current selection
        Span span ();

        // mark a selection
        Text select (int start=0, int length=int.max);

        // move the selection around
        bool select (T c);
        bool select (T[] pattern);
        bool select (TextView other);
        bool selectPrior (T c);
        bool selectPrior (T[] pattern);
        bool selectPrior (TextView other);

        // format behind current selection
        Text format (T[] format, ...);

        // append behind current selection
        Text append (T[] text);
        Text append (TextView other);
        Text append (T chr, int count=1);
        Text append (int value, options);
        Text append (long value, options);
        Text append (double value, options);
        Text append (InputStream source);

        // transcode behind current selection
        Text encode (char[]);
        Text encode (wchar[]);
        Text encode (dchar[]);

        // insert before current selection
        Text prepend (T[] text);
        Text prepend (TextView other);
        Text prepend (T chr, int count=1);

        // replace current selection
        Text replace (T chr);
        Text replace (T[] text);
        Text replace (TextView other);

        // remove current selection
        Text remove ();

        // clear content
        Text clear ();

        // trim leading and trailing whitespace
        Text trim ();

        // trim leading and trailing chr instances
        Text strip (T chr);

        // truncate at point, or current selection
        Text truncate (int point = int.max);

        // reserve some space for inserts/additions
        Text reserve (int extra);

        // write content to stream
        Text write (OutputStream sink);
}

class TextView(T) : UniText
{
        // hash content
        hash_t toHash ();

        // return length of content
        uint length ();

        // compare content
        bool equals  (T[] text);
        bool equals  (TextView other);
        bool ends    (T[] text);
        bool ends    (TextView other);
        bool starts  (T[] text);
        bool starts  (TextView other);
        int compare  (T[] text);
        int compare  (TextView other);
        int opEquals (Object other);
        int opCmp    (Object other);

        // copy content
        T[] copy (T[] dst);

        // return content
        T[] slice ();

        // return data type
        typeinfo encoding ();

        // replace the comparison algorithm
        Comparator comparator (Comparator other);
}

class UniText
{
        // convert content
        abstract char[]  toString  (char[]  dst = null);
        abstract wchar[] toString16 (wchar[] dst = null);
        abstract dchar[] toString32 (dchar[] dst = null);
}

void memmove(void* dst, void* src, uint bytes) [private, extern(C)] ¶#

class Text(T) : TextView!(T) ¶#

The mutable Text class actually implements the full API, whereas the superclasses are purely abstract (could be interfaces instead).

struct Span [public] ¶#

Selection span

uint begin ¶#

uint length ¶#

length of selection

this(uint space = 0) ¶#

Create an empty Text with the specified available space

Note:

A character like 'a' will be implicitly converted to uint and thus will be accepted for this constructor, making it appear like you can initialize a Text instance with a single character, something which is not supported.

this(T[] content, bool copy = true) ¶#

Create a Text upon the provided content. If said content is immutable (read-only) then you might consider setting the 'copy' parameter to false. Doing so will avoid allocating heap-space for the content until it is modified via Text methods. This can be useful when wrapping an array "temporarily" with a stack-based Text

this(TextViewT other, bool copy = true) ¶#

Create a Text via the content of another. If said content is immutable (read-only) then you might consider setting the 'copy' parameter to false. Doing so will avoid allocating heap-space for the content until it is modified via Text methods. This can be useful when wrapping an array temporarily with a stack-based Text

Text set(T[] chars, bool copy = true) [final] ¶#

Set the content to the provided array. Parameter 'copy' specifies whether the given array is likely to change. If not, the array is aliased until such time it is altered via this class. This can be useful when wrapping an array "temporarily" with a stack-based Text

Text set(TextViewT other, bool copy = true) [final] ¶#

Replace the content of this Text. If the new content is immutable (read-only) then you might consider setting the 'copy' parameter to false. Doing so will avoid allocating heap-space for the content until it is modified via one of these methods. This can be useful when wrapping an array "temporarily" with a stack-based Text

Text select(int start = 0, int length = int.max) [final] ¶#

Explicitly set the current selection

T[] selection() [final] ¶#

Return the currently selected content

Span span() [final] ¶#

Return the index and length of the current selection

bool select(T c) [final] ¶#

Find and select the next occurrence of a BMP code point in a string. Returns true if found, false otherwise

bool select(TextViewT other) [final] ¶#

Find and select the next substring occurrence. Returns true if found, false otherwise

bool select(T[] chars) [final] ¶#

Find and select the next substring occurrence. Returns true if found, false otherwise

bool selectPrior(T c) [final] ¶#

Find and select a prior occurrence of a BMP code point in a string. Returns true if found, false otherwise

bool selectPrior(TextViewT other) [final] ¶#

Find and select a prior substring occurrence. Returns true if found, false otherwise

bool selectPrior(T[] chars) [final] ¶#

Find and select a prior substring occurrence. Returns true if found, false otherwise

Text format(T[] format, ...) [final] ¶#

Append formatted content to this Text

Text append(TextViewT other) [final] ¶#

Append text to this Text

Text append(T[] chars) [final] ¶#

Append text to this Text

Text append(T chr, int count = 1) [final] ¶#

Append a count of characters to this Text

Text append(int v, T[] fmt = null) [final] ¶#

Append an integer to this Text

Text append(long v, T[] fmt = null) [final] ¶#

Append a long to this Text

Text append(double v, uint decimals = 2, int e = 10) [final] ¶#

Append a double to this Text

Text append(InputStream source) [final] ¶#

Append content from input stream at insertion point. Use tango.io.stream.Utf as a wrapper to perform conversion as necessary

Text prepend(T chr, int count = 1) [final] ¶#

Insert characters into this Text

Text prepend(T[] other) [final] ¶#

Insert text into this Text

Text prepend(TextViewT other) [final] ¶#

Insert another Text into this Text

Text encode(char[] s) [final] ¶#

Text encode(wchar[] s) [final] ¶#

Text encode(dchar[] s) [final] ¶#

Text encode(Object o) [final] ¶#

Append encoded text at the current selection point. The text is converted as necessary to the appropritate utf encoding.

Text replace(T chr) [final] ¶#

Replace a section of this Text with the specified character

Text replace(T[] chars) [final] ¶#

Replace a section of this Text with the specified array

Text replace(TextViewT other) [final] ¶#

Replace a section of this Text with another

Text remove() [final] ¶#

Remove the selection from this Text and reset the selection to zero length (at the current position)

Text remove(int start, int count) [private] ¶#

Remove the selection from this Text

Text truncate(int index = int.max) [final] ¶#

Truncate this string at an optional index. Default behaviour is to truncate at the current append point. Current selection is moved to the truncation point, with length 0

Text clear() [final] ¶#

Clear the string content

Text trim() [final] ¶#

Remove leading and trailing whitespace from this Text, and reset the selection to the trimmed content

Text strip(T matches) [final] ¶#

Remove leading and trailing matches from this Text, and reset the selection to the stripped content

Text reserve(uint extra) [final] ¶#

Reserve some extra room

Text write(OutputStream sink) ¶#

Write content to output stream

TypeInfo encoding() [final] ¶#

Get the encoding type

Comparator comparator(Comparator other) [final] ¶#

Set the comparator delegate. Where other is null, we behave as a getter only

hash_t toHash() [override] ¶#

Hash this Text

uint length() [final] ¶#

Return the length of the valid content

bool equals(TextViewT other) [final] ¶#

Is this Text equal to another?

bool equals(T[] other) [final] ¶#

Is this Text equal to the provided text?

bool ends(TextViewT other) [final] ¶#

Does this Text end with another?

bool ends(T[] chars) [final] ¶#

Does this Text end with the specified string?

bool starts(TextViewT other) [final] ¶#

Does this Text start with another?

bool starts(T[] chars) [final] ¶#

Does this Text start with the specified string?

int compare(TextViewT other) [final] ¶#

Compare this Text start with another. Returns 0 if the content matches, less than zero if this Text is "less" than the other, or greater than zero where this Text is "bigger".

int compare(T[] chars) [final] ¶#

Compare this Text start with an array. Returns 0 if the content matches, less than zero if this Text is "less" than the other, or greater than zero where this Text is "bigger".

T[] copy(T[] dst) [final] ¶#

Return content from this Text

A slice of dst is returned, representing a copy of the content. The slice is clipped to the minimum of either the length of the provided array, or the length of the content minus the stipulated start point

T[] slice() [final] ¶#

Return an alias to the content of this TextView. Note that you are bound by honour to leave this content wholly unmolested. D surely needs some way to enforce immutability upon array references

char[] toString(char[] dst = null) [final] ¶#

wchar[] toString16(wchar[] dst = null) [final] ¶#

dchar[] toString32(dchar[] dst = null) [final] ¶#

Convert to the UniText types. The optional argument dst will be resized as required to house the conversion. To minimize heap allocation during subsequent conversions, apply the following pattern:

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_Text string; wchar[] buffer; wchar[] result = string.utf16 (buffer); if (result.length > buffer.length) buffer = result;

You can also provide a buffer from the stack, but the output will be moved to the heap if said buffer is not large enough

int opCmp(Object o) [override] ¶#

Compare this Text to another. We compare against other Strings only. Literals and other objects are not supported

int opEquals(Object o) [override] ¶#

int opEquals(T[] s) [final] ¶#

Is this Text equal to the text of something else?

void pinIndex(inout int x) [private] ¶#

Pin the given index to a valid position.

void pinIndices(inout int start, inout int length) [private] ¶#

Pin the given index and length to a valid position.

int simpleComparator(T[] a, T[] b) [private] ¶#

Compare two arrays. Returns 0 if the content matches, less than zero if A is "less" than B, or greater than zero where A is "bigger". Where the substrings match, the shorter is considered "less".

void expand(uint index, uint count) [private] ¶#

Make room available to insert or append something

Text set(T chr, uint start, uint count) [private] ¶#

Replace a section of this Text with the specified character

void realloc(uint count = 0) [private] ¶#

Allocate memory due to a change in the content. We handle the distinction between mutable and immutable here.

Text append(T* chars, uint count) [private] ¶#

Internal method to support Text appending

class TextView(T) : UniText ¶#

Immutable string

uint length() [abstract] ¶#

Return the length of the valid content

bool equals(TextView other) [abstract] ¶#

Is this Text equal to another?

bool equals(T[] other) [abstract] ¶#

Is this Text equal to the the provided text?

bool ends(TextView other) [abstract] ¶#

Does this Text end with another?

bool ends(T[] chars) [abstract] ¶#

Does this Text end with the specified string?

bool starts(TextView other) [abstract] ¶#

Does this Text start with another?

bool starts(T[] chars) [abstract] ¶#

Does this Text start with the specified string?

int compare(TextView other) [abstract] ¶#

Compare this Text start with another. Returns 0 if the content matches, less than zero if this Text is "less" than the other, or greater than zero where this Text is "bigger".

int compare(T[] chars) [abstract] ¶#

Compare this Text start with an array. Returns 0 if the content matches, less than zero if this Text is "less" than the other, or greater than zero where this Text is "bigger".

T[] copy(T[] dst) [abstract] ¶#

Return content from this Text. A slice of dst is returned, representing a copy of the content. The slice is clipped to the minimum of either the length of the provided array, or the length of the content minus the stipulated start point

int opCmp(Object o) [abstract] ¶#

Compare this Text to another

int opEquals(Object other) [abstract] ¶#

Is this Text equal to another?

int opEquals(T[] other) [abstract] ¶#

Is this Text equal to another?

TypeInfo encoding() [abstract] ¶#

Get the encoding type

Comparator comparator(Comparator other) [abstract] ¶#

Set the comparator delegate

hash_t toHash() [abstract] ¶#

Hash this Text

T[] slice() [abstract] ¶#

Return an alias to the content of this TextView. Note that you are bound by honour to leave this content wholly unmolested. D surely needs some way to enforce immutability upon array references

class UniText ¶#

A string abstraction that converts to anything