Python story generator.

from __future__ import print_function
import sys, codecs, random, string, re

# just a simple story generator
# let me know what you do with it
# tweet -> @eigenbom

# expands a term, using a grammar and a world (a dictionary of concrete things)
def expand(grammar, world, start_term):
    m = re.search('[.*]', start_term)
    e2 = start_term

    def repl(matchobj):
        m = matchobj.group(1)
        attrib = (matchobj.group(0)[0]=="$")

        matched = ((not attrib) and m in grammar) or (attrib and m in world)
        if not matched:
            # not yet matched .. so hold off?
            return matchobj.group(0)

        if attrib: e = world[m]
        else: e = grammar[m]
        replacement = None
        if type(e) is list:
            replacement = random.choice(e)
        elif hasattr(e, '__call__'): # if function
            replacement = e(grammar, world, e2)
        else:
            replacement = e

        # if replacement is concrete, add it to the world ...
        if not attrib:
            world[m] = replacement
            # pprint(world)
        return replacement

    while True:
        # then expand
        e1 = re.sub('\[(\w*)\]', repl, e2)
        e1 = re.sub('\$(\w*)', repl, e1)
        if e1 == e2: break
        else: e2 = e1

    return e2

# shorthand
def o(str):
        return [s for s in str.split(",")]

def generate_story():
    grammar = dict(
        raised_by_2 = o("wolves,donkeys,goats"),
        raised_by = o("[raised_by_2],violent [raised_by_2],happy [raised_by_2]"),
        raise_location = o("forest,lake,ruins,marsh,castle,swamp"),
        loc_adj = o("dark,pleasant,never-ending,smelly"),
        raise_location_desc = o("[raise_location],[loc_adj] [raise_location]"),
        raised_where = [
            " in a [raise_location_desc]",
            " near a [raise_location_desc]",
            " nowhere near a [raise_location_desc]",
            None],
        raised = [
            "was raised by [raised_by][raised_where]",
            "grew up around [raised_by][raised_where]"],
        major_skill = o("dance,socialise,paint"),
        minor_skill = o("knit,sleep,criticise"),
        growing_up_2 = [
            " and [minor_skill]",
            ", but $he was more interested in how to [minor_skill]",
            " and, to a lesser extent, how to [minor_skill]",
            ", but ate a lot of $fav_food",
            " and eat $fav_food",
            None
        ],
        growing_up = [
            "The $raised_by_2 taught [him] how to [major_skill][growing_up_2]",
            "$he learnt how to [major_skill][growing_up_2]",
            "Early on, $he took a fascination to [major_skill][growing_up_2]"
            ],
        enemy = o("a dragon,a ghost,a troll,a battletoad"),
        enemy_action = [
            " and stole [his] $fav_food.",
            ", demanding that $he $major_skill.",
            " and smiled.",
        ],
        event = ["[enemy] appeared[enemy_action]", "nothing much happened"],
        event_start = ["One day, ", "Once, while wandering in the $raise_location, ", "Minding [his] own business, suddenly ", None],
        story = "$he [raised]. [growing_up]. [event_start][event].",

        # helpers
        him = lambda g,w,_: "him" if w["he"]=="he" else "her",
        his = lambda g,w,_: "his" if w["he"]=="he" else "her",
    )

    world = {}
    # add a few details
    world["he"] =  "he" if random.random()>0.5 else "she"
    world["fav_food"] = random.choice(["spaghetti","weetbix","sandwich","pies"])

    history = expand(grammar, world, "[story]")
    sentences = [s.strip() for s in history.split(".")]
    sentences = [s.capitalize() + "." for s in sentences if len(s)>0]
    history = " ".join(sentences).strip()
    return history

if __name__=="__main__":
    print(generate_story())