Class Visitor¶

Defined in File Blackbird.h

Inheritance Relationships¶

Base Type¶

public blackbirdBaseVisitor

Class Documentation¶

class blackbird::Visitor : public blackbirdBaseVisitor¶

The main Blackbird visitor. This visitor is invoked implicitly via the parse function to parse the Blackbird script.

The methods defined in this class describe how to traverse the abstract syntax tree describing the blackbird program, how to extract and evaluate arrays, variables, expressions, and quantum programs.

Public Functions

template<class O> O *_create_operation(blackbirdParser::ArgumentsContext *ctx, intvec modes)¶

Factory function to create Blackbird operations corresponding to those provided in the Blackbird script.

Parameters

ctx – ArgumentsContext
modes – std::vector<int> containing the modes the operation is applied to

Returns

the operation

antlrcpp::Any visitNumber(blackbirdParser::NumberContext *ctx)¶

Defines what the visitor does when a NumberContext is visited.

Here, it gets the string representing the number, and calls various helper functions to convert Blackbird complex, float, and int to the C++ equivalent.

Parameters: ctx – NumberContext
Returns: returns the number literal

antlrcpp::Any visitExpressionvar(blackbirdParser::ExpressionvarContext *ctx)¶

Defines what the visitor does when an ExpressionvarContext is visited.

Here, it gets the variable name and the variable type, and starts the process of extracting the variable based on the declared type.

Parameters: ctx – ExpressionvarContext
Returns: returns 0 to indicate successful visitation

antlrcpp::Any visitArrayvar(blackbirdParser::ArrayvarContext *ctx)¶

Defines what the visitor does when a ArrayvarContext is visited.

Here, it gets the name and type of the array variable, initializes a vector corresponding to the declared type, and stores it either in the complexmat_vars, floatmat_vars, or intmat_vars dictionary.

Parameters: ctx – NumberContext

antlrcpp::Any visitArrayrow(blackbirdParser::ArrayrowContext*)¶

Defines what the visitor does when a ArrayrowContext is visited.

Here, it extracts the column element values, and populates the row by manually visiting each child element.

Parameters: ctx – ArrayrowContext
Returns: the array row vector

antlrcpp::Any visitStatement(blackbirdParser::StatementContext *ctx)¶

Defines what to do as each quantum operation in the device context is visited.

In general, this includes:

Getting the number of modes the operation is applied to using split_string_to_ints
If the statement is an operation:
- Get the number of arguments/types of the arguments
- Evaluate the arguments
- Use _create_operation template to create the new operation object, acting
  
  on the specified number of modes, with the specified arguments
- Add this operation to the program->operations vector.
Repeat the previous steps for any measurements.

Parameters: ctx – StatementContext
Returns: 0 to specify correct visitation.

antlrcpp::Any visitProgram(blackbirdParser::ProgramContext *ctx)¶

Defines what to do as each quantum operation in the device context is visited.

In general, this includes:

Getting the number of modes the operation is applied to using split_string_to_ints
If the statement is an operation:
- Get the number of arguments/types of the arguments
- Evaluate the arguments
- Use _create_operation template to create the new operation object, acting
  
  on the specified number of modes, with the specified arguments
- Add this operation to the program->operations vector.
Repeat the previous steps for any measurements.

Parameters: ctx – StatementContext
Returns: 0 to specify correct visitation.

antlrcpp::Any visitStart(blackbirdParser::StartContext *ctx)¶

Starts the visitation process of parsing the Blackbird code.

Parameters: ctx – StartContext
Returns: returns the blackbird program, containing device information, metadata, and the quantum program to run

Public Members

std::unordered_map<std::string, std::complex<double>> complex_vars¶: Unordered map mapping from blackbird complex variable names to std::complex<double> values.

std::unordered_map<std::string, double> float_vars¶: Unordered map mapping from blackbird float variable names to double values

std::unordered_map<std::string, int> int_vars¶: Unordered map mapping from blackbird int variable names to int values

std::unordered_map<std::string, std::string> str_vars¶: Unordered map mapping from blackbird string variable names to std::string values

std::unordered_map<std::string, bool> bool_vars¶: Unordered map mapping from blackbird bool variable names to bool values

std::unordered_map<std::string, complexmat> complexmat_vars¶: Unordered map mapping from blackbird complex array variable names to complexmat values.

std::unordered_map<std::string, floatmat> floatmat_vars¶: Unordered map mapping from blackbird float array variable names to floatmat values.

std::unordered_map<std::string, intmat> intmat_vars¶: Unordered map mapping from blackbird int array variable names to intmat values.

Program *program¶: quantum Program that is populated by the Visitor