Package edu.hws.jcm.data
Class SymbolTable
java.lang.Object
edu.hws.jcm.data.SymbolTable
- All Implemented Interfaces:
Serializable
A symbol table contains MathObjects, associating them
with their names. To support scoping (for example), a symbol
table can have a parent symbol table. If a symbol is not found
in the table itself, the search procedes to its parent.
MathObjects in the parent are hidden by MathObjects of
the same name in a SymbolTable.
Note that a NullPointerException error will occur if an
attempt is made to add a MathObject with a null name to a
SymbolTable.
A MathObject should not be renamed while it is registered
in a SymbolTable.
Note that a Parser has an associated SymbolTable. I expect
SymbolTables to be used only through Parsers.
- See Also:
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Method Summary
Modifier and TypeMethodDescriptionvoid
add
(MathObject sym) Adds sym to the SymbolTable, associating it with its name.void
add
(String name, MathObject sym) Adds the given MathObject, sym, to the symbol table, associating it with the given name (which is probably the name of the symbol or that name transformed to lower case, but it doesn't have to be).Look up the object with the given name, if any.void
Remove the object with the given name from the symbol table, but NOT from the parent symbol table.
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Method Details
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get
Look up the object with the given name, if any. If not found, return null. (If the name is not found in the HashTable, symbols, the search is delegated to the parent.) If the name is null, then null is returned. -
add
Adds sym to the SymbolTable, associating it with its name. -
add
Adds the given MathObject, sym, to the symbol table, associating it with the given name (which is probably the name of the symbol or that name transformed to lower case, but it doesn't have to be). If the same name is already in use in the HashTable then the new object replaces the current object. Note that if the name is defined in the parent symbol table, then the old object is hidden, not removed from the parent. If sym is null or if sym's name is null, than a NullPointerException is thrown. -
remove
Remove the object with the given name from the symbol table, but NOT from the parent symbol table. No error occurs if the name is not in the table or if name is null. If an object of the same name occurs in the parent, this routine will un-hide it.
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