B2Lexer Class Reference

Inheritance diagram for B2Lexer:

Collaboration diagram for B2Lexer:

Public Member Functions
def	__init__ (self)
def	LBRACK (self, t)
def	RBRACK (self, t)
def	LPAREN (self, t)

Public Attributes
	control_token_stack
	control_token_stack (list): stack for keeping track of seen brackets and parenthesis. More...

Static Public Attributes
dictionary	cut_tokens
	cut specific tokens More...
dictionary	expression_tokens
	expression tokens, also needed for cut. More...
dictionary	tokens = expression_tokens.union(cut_tokens)
	Set of all tokens.
string	ignore = " \t\n"
	ignore spaces tabs and newlines
dictionary	literals = {r","}
	comma token definition as literal
string	EQUALEQUAL = r"=="
	token regular expression for '=='
string	GREATEREQUAL = r">="
	token regular expression for '>='
string	LESSEQUAL = r"<="
	token regular expression for '<='
string	GREATER = r">"
	token regular expression for '>'
string	LESS = r"<"
	token regular expression for '<'
string	NOTEQUAL = r"!="
	token regular expression for '!='
string	POWER = r"\*\*|\^"
	token regular expression for power, both '**' and '^' allowed
string	TIMES = r"\*"
	token regular expression for '*'
string	DIVIDE = r"/"
	token regular expression for '/'
string	PLUS = r"\+"
	token regular expression for '+'
string	MINUS = r"-"
	token regular expression for '-'

Detailed Description

Class responsible for scanning the cut and generating a stream of tokens.
The token stream can be passed to `B2Parser` to generate a syntax tree.

Definition at line 73 of file b2parser.py.

Constructor & Destructor Documentation

__init__()

def __init__

(

self

)

Initialize Lexer

Definition at line 79 of file b2parser.py.

Member Function Documentation

LBRACK()

def LBRACK	(		self,
			t
	)

Scan opening bracket.

Parameters:
    t (sly.lex.token): token of type LBRACK

Raises:
    SyntaxError: if no following closing bracket is found
        in the input.

Side Effect:
    Pushes 'BRACK' onto control_token_stack

Returns:
    sly.lex.Token

Definition at line 146 of file b2parser.py.

LPAREN()

def LPAREN	(		self,
			t
	)

Scan opening parenthesis.

Parameters:
    t (sly.lex.token): token of type LPAREN

Raises:
    SyntaxError: if no following closing parenthesis is found
        in the input.

Side Effect:
    Pushes 'PAREN' onto control_token_stack

Returns:
    sly.lex.Token

Definition at line 198 of file b2parser.py.

RBRACK()

def RBRACK	(		self,
			t
	)

Scan closing bracket.

Parameters:
    t (sly.lex.token): token of type RBRACK

Raises:
    SyntaxError: 1. If control_token_stack is empty, which means
        no bracket was opened previously.
                 2. If state of control_token_stack is 'PAREN', which
        means a closing parenthesis is expected.

Side Effect:
    Pops object from control_token_stack

Returns:
    sly.lex.Token

Definition at line 169 of file b2parser.py.

Member Data Documentation

control_token_stack

control_token_stack

control_token_stack (list): stack for keeping track of seen brackets and parenthesis.

Allows finding parenthesis and bracket syntax errors on scanner level.

Definition at line 84 of file b2parser.py.

cut_tokens

dictionary cut_tokens

static

Initial value:

=  {
        # structure tokens
        RBRACK, LBRACK,  # noqa: F821
        # boolean operators
        AND, OR, NOT,  # noqa: F821
        # comparison operators
        EQUALEQUAL, GREATEREQUAL, LESSEQUAL, GREATER, LESS,  # noqa: F821
        NOTEQUAL,  # noqa: F821
    }

cut specific tokens

Definition at line 87 of file b2parser.py.

expression_tokens

dictionary expression_tokens

static

Initial value:

=  {
        LPAREN, RPAREN,  # noqa: F821
        # data types
        DOUBLE, INTEGER, IDENTIFIER, BOOLEAN,  # noqa: F821
        # arithmetic operators
        POWER, TIMES, DIVIDE, PLUS, MINUS  # noqa: F821
    }

expression tokens, also needed for cut.

Definition at line 97 of file b2parser.py.

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The documentation for this class was generated from the following file:

• framework/scripts/b2parser.py