Most efficient way to modify variables within a custom grammar?

Question

I'm working with a propriety driving simulator which generates "scenario" files in a customised version of Scilab. I am provided a single 11,000 line long "master" file, and from this I need to replace certain values to generate n versions of the scenario.

A minimal example of the syntax for a single parent TASK would be something like this:

TYPEOF TASK (57)
{
    LABEL="Dot 3a"/*replace with name for name in list */
    TASK_KIND="0"

    TYPEOF VARIABLE (53)
    {
        LABEL="Time1"
        TYPE="FLOAT"
        VALUE="14.000000" /* replace with random.integer() */
        INTERACTIVE="VOID"

    TYPEOF VARIABLE (54)
    {
        LABEL="X_pos1"
        TYPE="FLOAT"
        VALUE="23.600000" 
        INTERACTIVE="VOID"


    TYPEOF TASK (58)
    {
        LABEL="Task: ISI"
        TASK_KIND="0"

        TYPEOF RULE (115)
        {
            LABEL="Rule: Go to subtask after Time1 seconds"

            TYPEOF CONDITION (SUPERIOR)
            {
                IS_EXPANDED="1"
                MODIFIER="BECOMES_TRUE"

                TYPEOF PARAMETER (OPERAND_1)
                {
                    KIND="FUNCTION"

                    TYPEOF FUNCTION (GET_TASK_CLOCK)
                    {
                    }
                    OWNER_FILE=""
                }

                TYPEOF PARAMETER (OPERAND_2)
                {
                    KIND="VARIABLE"
                    VALUE="53"
                    OWNER_FILE=""
                }
            }

            TYPEOF ACTION (GOTO_TASK)
            {
                IS_EXPANDED="1"

                TYPEOF PARAMETER (TASK_NUMBER)
                {
                    KIND="ENUM"
                    VALUE="GOTO_NEXT_TASK"
                    OWNER_FILE=""
                }
            }
        }
    }

I need to replace certain values in this script with standard input. For instance, have a list of names which will replace the value of LABEL under a parent level TASK; and have to replace VALUE for first parent VARIABLE with a random number between 6 and 16.

My first solution was Python REGEX based, something like follows (but for every value I seek to change):

for row in scenarioInput:
    parenttaskmatch = re.search("^		TYPEOF TASK",row)
    if parenttaskmatch:
        replacementrow = re.sub(r"([0-9]{1,3})",repl,row)

It was suggested to me that I could write a custom grammar with something like Parsimonious and then regenerate the output with Mustache.

from parsimonious.grammar import Grammar
grammar = Grammar(r"""
    any = task / data
    task = "TYPEOF " key " (" number ")" newline open_curly any+ close_curly
    data = key "=" quote text quote newline
    open_curly = "{" newline
    close_curly = "}" newline
    key = ~"[A-Z 0-9_]*"
    text = ~"[A-Z0-9 ]*"i
    number = ~"[0-9]*"
    newline = "
"
    space = " "
    quote = """
""")

text = open('example_driving_rule.sci').read()
grammar.parse(text)
# Note doesn't work

As you can see, this is not an efficient solution to the problem either. What do you guys think is a better solution?

Most efficient way to modify variables within a custom grammar?

Answers (1)

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