ICU 60.1  60.1
Public Types | Public Member Functions
icu::SymbolTable Class Referenceabstract

An interface that defines both lookup protocol and parsing of symbolic names. More...

#include <symtable.h>

Public Types

enum  { SYMBOL_REF = 0x0024 }
 The character preceding a symbol reference name. More...
 

Public Member Functions

virtual ~SymbolTable ()
 Destructor. More...
 
virtual const UnicodeStringlookup (const UnicodeString &s) const =0
 Lookup the characters associated with this string and return it. More...
 
virtual const UnicodeFunctorlookupMatcher (UChar32 ch) const =0
 Lookup the UnicodeMatcher associated with the given character, and return it. More...
 
virtual UnicodeString parseReference (const UnicodeString &text, ParsePosition &pos, int32_t limit) const =0
 Parse a symbol reference name from the given string, starting at the given position. More...
 

Detailed Description

An interface that defines both lookup protocol and parsing of symbolic names.

A symbol table maintains two kinds of mappings. The first is between symbolic names and their values. For example, if the variable with the name "start" is set to the value "alpha" (perhaps, though not necessarily, through an expression such as "$start=alpha"), then the call lookup("start") will return the char[] array ['a', 'l', 'p', 'h', 'a'].

The second kind of mapping is between character values and UnicodeMatcher objects. This is used by RuleBasedTransliterator, which uses characters in the private use area to represent objects such as UnicodeSets. If U+E015 is mapped to the UnicodeSet [a-z], then lookupMatcher(0xE015) will return the UnicodeSet [a-z].

Finally, a symbol table defines parsing behavior for symbolic names. All symbolic names start with the SYMBOL_REF character. When a parser encounters this character, it calls parseReference() with the position immediately following the SYMBOL_REF. The symbol table parses the name, if there is one, and returns it.

Stable:
ICU 2.8

Definition at line 56 of file symtable.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

The character preceding a symbol reference name.

Stable:
ICU 2.8

Definition at line 63 of file symtable.h.

Constructor & Destructor Documentation

◆ ~SymbolTable()

virtual icu::SymbolTable::~SymbolTable ( )
virtual

Destructor.

Stable:
ICU 2.8

Member Function Documentation

◆ lookup()

virtual const UnicodeString* icu::SymbolTable::lookup ( const UnicodeString s) const
pure virtual

Lookup the characters associated with this string and return it.

Return NULL if no such name exists. The resultant string may have length zero.

Parameters
sthe symbolic name to lookup
Returns
a string containing the name's value, or NULL if there is no mapping for s.
Stable:
ICU 2.8

◆ lookupMatcher()

virtual const UnicodeFunctor* icu::SymbolTable::lookupMatcher ( UChar32  ch) const
pure virtual

Lookup the UnicodeMatcher associated with the given character, and return it.

Return NULL if not found.

Parameters
cha 32-bit code point from 0 to 0x10FFFF inclusive.
Returns
the UnicodeMatcher object represented by the given character, or NULL if there is no mapping for ch.
Stable:
ICU 2.8

◆ parseReference()

virtual UnicodeString icu::SymbolTable::parseReference ( const UnicodeString text,
ParsePosition pos,
int32_t  limit 
) const
pure virtual

Parse a symbol reference name from the given string, starting at the given position.

If no valid symbol reference name is found, return the empty string and leave pos unchanged. That is, if the character at pos cannot start a name, or if pos is at or after text.length(), then return an empty string. This indicates an isolated SYMBOL_REF character.

Parameters
textthe text to parse for the name
poson entry, the index of the first character to parse. This is the character following the SYMBOL_REF character. On exit, the index after the last parsed character. If the parse failed, pos is unchanged on exit.
limitthe index after the last character to be parsed.
Returns
the parsed name, or an empty string if there is no valid symbolic name at the given position.
Stable:
ICU 2.8

The documentation for this class was generated from the following file: