ptera.opparse

Parser for the selector syntax.

class ptera.opparse.ASTNode(parts)

Node that results from parsing.

args

List of arguments.

ops

List of operators. Generally one less than the number of arguments.

key

String key that represents the kind of operation we are dealing with: which arguments are non-null and what the ops are. If args == [a, b, None] and ops == [+, -] then key == “X + X - _”.

location

Location of the node in the source code. It encompasses the locations of all args and ops.

class ptera.opparse.Lexer(definitions)

The Lexer splits source code into Tokens.

class ptera.opparse.OperatorPrecedenceTower(operators)

Compare operators using a simple operator tower.

resolve(op)

Resolve the priority tuple for a given op.

class ptera.opparse.Parser(lexer, order)

Operator precedence parser.

finalize(parts)

Clean up a list of parts that form a completed ASTNode.

• If the parts are [None, op, None], this is just the op.

• If the parts are [arg1, op1, arg2, op2, … argn] then we create an ASTNode with the given args and ops.

process(tokens)

Process a list of tokens.

class ptera.opparse.Token(value, type, source, start, end)

Token produced by the lexer.

value

Textual value of the token.

type

Type of the token.

location

Location of the token.

ptera.opparse.cbrack(prio)

Create a priority tuple for a closing bracket.

ptera.opparse.lassoc(prio)

Create a priority tuple for a left-associative operator.

ptera.opparse.obrack(prio)

Create a priority tuple for an opening bracket.

ptera.opparse.rassoc(prio)

Create a priority tuple for a right-associative operator.