titus.pfaast.LiteralNull¶

class titus.pfaast.LiteralNull(pos=None)[source]¶

Bases: titus.pfaast.LiteralValue

Abstract syntax tree for a literal null.

class Context(retType, calls)¶

Bases: titus.pfaast.ExpressionContext

__init__(retType, calls)¶

LiteralNull.__init__(pos=None)¶

LiteralNull.desc = '(null)'¶

LiteralNull.jsonNode(lineNumbers, memo)¶

Convert this abstract syntax tree to Pythonized JSON.

Parameters:	lineNumbers (bool) – if True, include locator marks in each JSON object memo (set of string) – used to avoid recursion; provide an empty set if unsure
Return type:	Pythonized JSON
Returns:	JSON representation

LiteralNull.walk(task, symbolTable, functionTable, engineOptions, version)¶

Walk over tree applying a titus.pfaast.Task while checking for semantic errors.

This is how Python is generated from an abstract syntax tree: the titus.pfaast.Task in that case is titus.genpy.GeneratePython.

Parameters:	task (titus.pfaast.Task) – generic task to perform on this abstract syntax tree node’s context symbolTable (titus.pfaast.SymbolTable) – used to look up symbols, cells, and pools functionTable (titus.pfaast.FunctionTable) – used to look up functions engineOptions (titus.options.EngineOptions) – implementation options version (titus.signature.PFAVersion) – version of the PFA language in which to interpret this PFA
Return type:	(titus.pfaast.AstContext, titus.pfaast.TaskResult)
Returns:	(information about this abstract syntax tree node after type-checking, result of the generic task)