SpiceVarExpr.py

from fysom import Fysom
from tokenize import generate_tokens, NAME, NUMBER, OP, ENDMARKER
from io import StringIO

class SpiceVarExpr:

    def __init__(self):
        self.outExpr= ''
        self.waveType= ''
        self.waveName= ''
        self.datasetName= 'r'
        self.fsm = Fysom({'initial': 'looking',
                      'events':
                      [
                            {'name': 'seeWaveVar', 'src':'looking', 'dst':'openParen'},
                          {'name': 'seeOpenParen', 'src':'openParen', 'dst':'inWaveVar'},
                          {'name': 'getWaveVar', 'src':'inWaveVar', 'dst':'closeParen'},
                          {'name': 'seeCloseParen', 'src':'closeParen', 'dst':'looking'},
                          {'name': 'reset', 'src':['looking', 'openParen', 'inWaveVar', 'closeParen'], 'dst':'looking'}
                          ],
                      'callbacks':{
                            'onseeWaveVar': self.onseeWaveVar,
                          'ongetWaveVar': self.ongetWaveVar,
                          'onseeCloseParen': self.onseeCloseParen,
                        }
                        })

    def datasetName(self, datasetName):
        self.dataset= datasetName

    def onseeWaveVar(self, e):
        self.waveType= e.msg

    def ongetWaveVar(self, e):
        self.waveName= e.msg

    def onseeCloseParen(self, e):
        self.outExpr += self.datasetName + "." + self.waveType + "('" + self.waveName + "')"


    # The state machine makes sure that the voltage or current expression follows the syntax.
    # If it doesn't, the machine backtracks and resets.
    # The non-matching text passes through.

    # Backtracking could be implemented with untokenize()

    # Problem: the tokenizer is not returning x1.3, it is returning x1.
    # Then the closing parenthesis, which is expected next, is not found.
    # This causes the state machine to backtrack and not translate to r['x1.3'] as it should.
    # Need to either fix the generate_tokens or the state machine to know to be able to
    # take more tokens to add to the state 'inWaveVar' before the closing paren.
    # Since generate_tokens is a big complicated module that someone else did,
    # need to handle the states here.
    #
    # This routine returns whitespace, which isn't always what is wanted.
    def fixWaveFormVariableNames(self, txt):
        self.outExpr= ''
        lastToknum= 0
        g = generate_tokens(StringIO(txt).readline)

        try:
            for toknum, tokval, _, _, _  in g:

                if self.fsm.current == "looking":
                    if toknum == NAME and (tokval == 'v' or tokval == 'i'):
                        self.fsm.seeWaveVar(msg=tokval)
                        continue

                elif self.fsm.current == "openParen":
                    if toknum == OP and tokval == '(':
                        self.fsm.seeOpenParen(msg=tokval)
                        continue
                    else:
                        self.outExpr += self.waveType
                        self.fsm.reset()

                elif self.fsm.current == 'inWaveVar':
                    if toknum == NAME or toknum == NUMBER:
                        self.fsm.getWaveVar(msg=tokval)
                        continue
                    else:
                        self.outExpr += self.waveType + '('
                        self.fsm.reset()

                # This appends subcircuit extended net names while still inside parens.
                elif self.fsm.current == 'closeParen' and tokval != ')':
                    self.waveName += tokval
                    continue

                elif self.fsm.current== 'closeParen':
                    if toknum == OP and tokval == ')':
                        self.fsm.seeCloseParen(msg=tokval)
                        continue
                    else:
                        self.outExpr += self.waveType + '(' + self.waveName
                        self.fsm.reset()

                self.outExpr += tokval

                if toknum == ENDMARKER:
                    # If the only difference is that whitespace has been removed, restore the original
                    out= txt
                    out = txt.replace(" ", "")
                    if out == self.outExpr:
                        return txt
                    else:
                        return self.outExpr
            else:
                print("Unexpected end of token parsing.")
                return txt
        except:
            print("Parsing failed")
            return txt

if __name__ == "__main__":

    # TODO: learn a python testing framework and use it here
    sve= SpiceVarExpr()

    inputExpression= 'yellow[20 30]'
    outputExpression= sve.fixWaveFormVariableNames(inputExpression)
    print("Input: " + inputExpression)
    print("Output: " + outputExpression)
    print("-----")

    inputExpression= 'v(1a)+2+v(v1)+av(v2)+vi(i)+i(i)'
    outputExpression= sve.fixWaveFormVariableNames(inputExpression)
    print("Input: " + inputExpression)
    print("Output: " + outputExpression)
    print("-----")

    inputExpression= '3.04m+v1+v(a)+v(b)+i(r1)*10k'
    outputExpression= sve.fixWaveFormVariableNames(inputExpression)
    print("Input: " + inputExpression)
    print("Output: " + outputExpression)

    inputExpression= ')'
    outputExpression= sve.fixWaveFormVariableNames(inputExpression)
    print("Input: " + inputExpression)
    print("Output: " + outputExpression)

    inputExpression= 'v(x1.3)'
    outputExpression= sve.fixWaveFormVariableNames(inputExpression)
    print("Input: " + inputExpression)
    print("Output: " + outputExpression)

    inputExpression= 'i(l.x1.l1)'
    outputExpression= sve.fixWaveFormVariableNames(inputExpression)
    print("Input: " + inputExpression)
    print("Output: " + outputExpression)