`class PDI::Expression`

Content

Member Functions

Expression ( ): Builds an empty expression.
Expression ( const Expression & expr ): Copies an expression.
Expression ( Expression && expr ): Moves an expression.
Expression ( const char * expr ): Builds (i.e.
Expression ( const std::string & expr ): Builds (i.e.
Expression ( long expr ): Builds an expression that represents an integer.
Expression ( double expr ): Builds an expression that represents a float.
Expression ( PC_tree_t expr ): Builds an expression that is parsed from PC_tree_t.
operator bool ( ): Checks whether this is an empty expression.
Expression operator% ( const Expression & expr ): Modulo operator of an expression.
Expression operator* ( const Expression & expr ): Multiplication operator of an expression.
Expression operator+ ( const Expression & expr ): Summation operator of an expression.
Expression operator- ( const Expression & expr ): Subtraction operator of an expression.
Expression operator/ ( const Expression & expr ): Division operator of an expression.
Expression & operator= ( const Expression & expr ): Copies an expression.
Expression & operator= ( Expression && expr ): Moves an expression.
double to_double ( Context & ctx ): Evaluates an expression as a float.
long to_long ( Context & ctx ): Evaluates an expression as an integer.
Ref to_ref ( Context & ctx ): Evaluates an expression as a data reference.
Ref to_ref ( Context & ctx, const Datatype & type ): Evaluates an expression as a data reference.
std::string to_string ( Context & ctx ): Evaluates an expression as a string.
~Expression ( ): Destroys an expression.

Documentation

Member Functions

`Expression ( )`

Description

Builds an empty expression. No operation can be used on an empty expression, it can only be assigned to

`Expression ( const Expression & expr )`

Description

Copies an expression.

Parameters

expr: the expression to copy

`Expression ( Expression && expr )`

Description

Moves an expression.

Parameters

expr: the expression to move

`Expression ( const char * expr )`

Description

Builds (i.e.

parse) an expression from a string

The grammar of an expression is as follow:

/* parsing as a REFERENCE is preferred over OPERATION
   parsing as an OPERATION is preferred over STRING_LITERAL
*/
EXPRESSION     := REFERENCE | OPERATION | STRING_LITERAL
STRING_LITERAL := ( CHAR | '&#39; '&#39; | '&#39; '$'
| REFERENCE
| '$' '(' OPERATION ')'
)*
/* The operator descending precedence order is:

*, /, %: multiplication, division and modulo,
+, -: addition and subtraction,
<, >: less than and greater than,
=: equality,
&: logical AND,
|: logical OR.
/
OPERATION      := TERM ( OPERATOR TERM )

TERM           := ( INT_LITERAL | REFERENCE | '(' OPERATION ')' )
REFERENCE      := '$' ( IREFERENCE | '{' IREFERENCE '}' )
IREFERENCE     := ID ( '[' OPERATION ']' | '.' ID )*
INT_LITERAL ~= (0x)? [0-9]+ ( .  )
ID          ~= [a-zA-Z_][a-zA-Z0-9_]*
CHAR        ~= [^$\]
OPERATOR    ~= [|&=<>+-*/%]

Parameters

expr: the string to parse

`Expression ( const std::string & expr )`

Description

Builds (i.e.

parse) an expression from a string

The grammar of an expression is as follow:

/* parsing as a REFERENCE is preferred over OPERATION
   parsing as an OPERATION is preferred over STRING_LITERAL
*/
EXPRESSION     := REFERENCE | OPERATION | STRING_LITERAL
STRING_LITERAL := ( CHAR | '&#39; '&#39; | '&#39; '$'
| REFERENCE
| '$' '(' OPERATION ')'
)*
/* The operator descending precedence order is:

*, /, %: multiplication, division and modulo,
+, -: addition and subtraction,
<, >: less than and greater than,
=: equality,
&: logical AND,
|: logical OR.
/
OPERATION      := TERM ( OPERATOR TERM )

TERM           := ( INT_LITERAL | REFERENCE | '(' OPERATION ')' )
REFERENCE      := '$' ( IREFERENCE | '{' IREFERENCE '}' )
IREFERENCE     := ID ( '[' OPERATION ']' | '.' ID )*
INT_LITERAL ~= (0x)? [0-9]+ ( .  )
ID          ~= [a-zA-Z_][a-zA-Z0-9_]*
CHAR        ~= [^$\]
OPERATOR    ~= [|&=<>+-*/%]

Parameters

expr: the string to parse

`Expression ( long expr )`

Description

Builds an expression that represents an integer.

Parameters

expr: the integer value

`Expression ( double expr )`

Description

Builds an expression that represents a float.

Parameters

expr: the flaot value

`Expression ( PC_tree_t expr )`

Description

Builds an expression that is parsed from PC_tree_t.

Parameters

expr: the PC_tree_t value

`operator bool ( )`

Description

Checks whether this is an empty expression.

`Expression operator% ( const Expression & expr )`

Description

Modulo operator of an expression.

Parameters

expr: the expression to use modulo

Result

Expression as a result of modulo

`Expression operator* ( const Expression & expr )`

Description

Multiplication operator of an expression.

Parameters

expr: the expression to multiply

Result

Expression as a result of multiplication

`Expression operator+ ( const Expression & expr )`

Description

Summation operator of an expression.

Parameters

expr: the expression to add

Result

Expression as a result of sum

`Expression operator- ( const Expression & expr )`

Description

Subtraction operator of an expression.

Parameters

expr: the expression to subtract

Result

Expression as a result of subtraction

`Expression operator/ ( const Expression & expr )`

Description

Division operator of an expression.

Parameters

expr: the expression to divide

Result

Expression as a result of division

`Expression & operator= ( const Expression & expr )`

Description

Copies an expression.

Parameters

expr: the expression to copy

Result

*this

`Expression & operator= ( Expression && expr )`

Description

Moves an expression.

Parameters

expr: the expression to move`

Result

*this

`double to_double ( Context & ctx )`

Description

Evaluates an expression as a float.

Parameters

ctx

Result

the float value

`long to_long ( Context & ctx )`

Description

Evaluates an expression as an integer.

Parameters

ctx

Result

the integer value

`Ref to_ref ( Context & ctx )`

Description

Evaluates an expression as a data reference.

Parameters

ctx: the context in which to evaluate the expression

Result

the data reference

`Ref to_ref ( Context & ctx, const Datatype & type )`

Description

Evaluates an expression as a data reference.

Parameters

ctx: the context in which to evaluate the expression
type: the type of the created Ref

Result

the data reference

`std::string to_string ( Context & ctx )`

Description

Evaluates an expression as a string.

Parameters

ctx

Result

the string value

`~Expression ( )`

Description

Destroys an expression.

Last modified January 1, 0001