A common feature of basic loops is the break functionality, allowing the user to specify break points for their loop to stop. I've been creating a keyword to enable nesting loops in Robot Framework. This Nestable For Loop for Robot Framework includes the break functionality.
The basic code for a nestable Robot Framework For Loop is located here. This is a strict upgrade, in that it includes the break functionality in the form of the keyword Exit If.
Exit If requires a single argument: a Boolean expression written in a string. Loops.py includes two methods to work with this kind of expression: _is_boolean_string(string_in) and _evaluate_boolean_string(condition). _is_boolean_string returns True if the expression is a Boolean string (including unsupported Boolean expressions), and _evaluate_boolean_string returns True if the expression would logically evaluate to True.
Because the nature of this code is to be nestable, I need it to be as fast and efficient as possible, so I'm looking for performance and algorithm-based suggestions.
from robot.libraries.BuiltIn import BuiltIn
# TODO: Create new types of For Loops
# TODO: Implement While Loop
# TODO: Create Do-While Loops
class Loops(object):
def __init__(self):
self.selenium_lib = BuiltIn().get_library_instance('ExtendedSelenium2Library')
self.internal_variables = {}
def for_loop(self, loop_type, start, end, index_var, *keywords):
# Format the keywords
keywords = self._format_loop(*keywords)
# If I'm given a range of numbers...
if loop_type == 'IN RANGE':
# Clean out the internal variables from previous iterations
self.internal_variables = {}
# This is the actual looping part
for loop_iteration in range(int(start), int(end)):
keyword_set = self._index_var_swap(loop_iteration, index_var, *keywords)
# If it's a one-keyword list with no arguments, then I can use the fastest possible keyword to run it
if len(keyword_set) == 1:
BuiltIn().run_keyword(keyword_set)
# If it's a one-keyword list with arguments, then I can use a faster keyword to run it
elif 'AND' not in keyword_set:
# If the keyword isn't Exit If, then I can just run it normally.
if keyword_set[0].lower() != 'exit if':
BuiltIn().run_keyword(*keyword_set)
# If the keyword is Exit If, then I need to evaluate the keyword differently..
elif BuiltIn().run_keyword(*keyword_set):
break
# If it's a multiple-keyword list, then I have to use Run Keywords
else:
temp = self._run_keywords(*keyword_set)
if not temp:
break
def exit_if(self, condition):
return self._evaluate_boolean_string(condition)
def _format_loop(self, *keywords):
keywords = list(keywords) # I need to format the keywords as a list.
changed = False # Whether or not I changed anything in the previous iteration.
index = 0 # The item index I'm at in the list of keywords
del_list = [] # The list of items I need to delete
swap_list = [] # The list of items i need to swap to AND for the use of Run Keywords
def _new_variable():
# Default to a variable declaration of 'name='
t = 1
# If my variable declaration is 'name ='
if x[-2:] == ' =':
# Reflect that in the value of t
t = 2
# Count the number of cells until the end of the line
length = self._deliminator_search(index, x, *keywords)
if length == 3 and not BuiltIn().run_keyword_and_return_status("Keyword Should Exist", keywords[index + 1]):
# If I'm assigning a value to my variable
self._assign_internal_variable(x[:-t], str(keywords[index + 1]))
elif length == 3:
# If I'm assigning the result of a keyword without any arguments
self._assign_internal_variable_to_keyword(keywords[index][:-t], str(keywords[index + 1]))
else:
# If I'm assigning the result of a keyword with arguments
self._assign_internal_variable_to_keyword(keywords[index][:-t], keywords[index + 1],
keywords[index + 2:index + (length - 1)])
# Add the variable declaration code to the delete list.
del_list.extend(range(index - 1, index + length))
# For each argument
for x in keywords:
# Format it to a string
x = str(x)
# Assign new variables
if x[-1:] == '=':
_new_variable()
# If the previous element was not changed...
if not changed:
# If the current item is not the last one on the list...
if x != len(keywords) - 1:
# If the current item is a deliminator...
if x == '\\':
# If the next item is a deliminator, delete this item and set changed to True
if keywords[int(index) + 1] == '\\':
del_list.append(index)
changed = True
# If the next item is not a deliminator...
else:
# If this isn't the first deliminator on the list, swap it to an 'AND'
if index != 0:
swap_list.append(index)
changed = True
# If this deliminator is in position index=0, just delete it
else:
del_list.append(index)
changed = True
# If the current element is not a deliminator, then I don't need to touch anything.
# If the current element is the last one, then I don't need to touch anything
# If the previous element was changed, then I don't need to "change" this one...
elif changed:
changed = False
# ...but if it's a deliminator then I do need to set it up for the inner for loop it means.
if keywords[index] == '\\':
keywords[index] = keywords[index]*2
index = index + 1 # Advance the index
# These actually do the swapping and deleting
for thing in swap_list:
keywords[thing] = 'AND'
del_list.reverse()
for item in del_list:
del keywords[item]
# I also need to activate my variables for this set of keywords to run.
keywords = self._activate_variables(*keywords)
return keywords
def _assign_internal_variable(self, variable_name, assignment):
# This keyword works like any other keyword so that it can be activated by BuiltIn.run_keywords
self.internal_variables[variable_name] = assignment
def _assign_internal_variable_to_keyword(self, variable_name, keyword, *arguments):
# Uses assign_internal_variable to simplify code.
self._assign_internal_variable(variable_name, BuiltIn().run_keyword(keyword, *arguments))
def _activate_variables(self, *keywords):
# Initialize variables
keywords = list(keywords) # Cast keywords as a List
index = 0 # The index of the keyword I'm looking at
# For each keyword
for keyword in keywords:
keyword = str(keyword) # Cast keyword as a String
assignment = False # Whether or not the found variable name is in a variable assignment
for key in self.internal_variables.keys():
key = str(key) # Cast key as a String
# If I can find the key in the keyword and it's not an assignment...
if keyword.find(key) > -1 and not assignment:
# ...replace the text of the key in the keyword.
keywords[index] = keyword.replace(str(key), str(self.internal_variables[key]))
# If the keyword I'm looking at is an assignment...
if keyword.lower() == 'assign internal variable'\
and keyword.lower() != 'assign internal variable to keyword':
# ...then my next keyword is going to definitely be a known variable, so I don't want to touch it.
assignment = True
# If the keyword I'm looking at is not an assignment...
else:
# ...set assignment to False just in case the previous one happened to be an assignment.
assignment = False
index = index + 1 # Advance the index
# NOTE: Replaces the EXACT text, even if it's in another keyword or variable, so be very careful
return keywords # Return the list of keywords to be used in the format loop
@staticmethod
def _is_boolean_string(string_in):
# For all of the possible Boolean parameters...
for param in ['!', '<', '>', '=', '==']:
# Return whether or not the parameter is in the string.
if str(param) in str(string_in):
return True
return False
@staticmethod
def _evaluate_boolean_string(condition):
def _find_bool():
begin = len(condition) # Initialize the starting index as the last index in condition
# For all of the parameters...
for index in t[2]:
# Find the location of the start of the boolean parameters
temp = condition.find(str(t[1][int(index)]))
# If the location exists and is less than start...
if temp <= begin and temp != -1:
# Set start to the location
begin = temp
t[0][int(index)] = True
# If the input was bad, return -1
if sum(t[0]) > 2 or sum(t[0]) == 0 or begin == len(condition):
return -1
else:
return begin
def _eval(arg_1, arg_2):
if (t[0][1] or t[0][2]) and not (t[0][1] and t[0][2]): # If it has either > or < in it, but not both
if t[0][3]: # If it has = in it
if t[0][1]: # If it's >=
return arg_1 >= arg_2
else: # If it's <=
return arg_1 <= arg_2
else:
if t[0][1]: # If it's >
return arg_1 > arg_2
else: # If it's <
return arg_1 < arg_2
elif t[0][4]: # If it's ==
return arg_1 == arg_2
elif t[0][0] and t[0][3]: # If it's !=
return arg_1 != arg_2
else: # In case of Tester
return False
# Cast the condition as a string with no whitespaces
condition = str(condition).replace(" ", "")
# Initialize the t-table with default values
t = [[False, False, False, False, False],
['!', '<', '>', '=', '=='],
[0, 1, 2, 3, 4]]
# Find the start of the Boolean expression
start = _find_bool()
# Evaluate the expression
return _eval(condition[:start], condition[start + sum(t[0]):])
@staticmethod
def _run_keywords(*keys):
# Find the end of the current keyword
def _and_search(start, key='no key yet'):
# I'm starting with a false key that is never 'AND'
and_index = 1 # I never want to start on an 'AND'
# While the current key isn't 'AND' and I'm not at the end of the list of keywords...
while key != 'AND' and and_index + start != len(key_list):
# Set the current key equal to the next key in the list.
key = key_list[int(start) + and_index]
and_index = and_index + 1 # Advance the index
# If the final key is an 'AND'...
if key == 'AND':
return and_index - 1 # Return the keyword length minus the 'AND'
# Otherwise...
else:
return and_index # Return the keyword length
def _split_keyword_list():
first = True # We always start at the first cell of a keyword/argument set.
index = 0 # The item index I'm at in the list of keywords
# For each word in the list of keywords/arguments...
for word in key_list:
# If it's the first word...
if first:
# Append the keyword
keywords.append(key_list[int(index):(index + _and_search(index))])
first = False # Set first to False
# If it's any other word I don't need to append it, but...
else:
# If it's the last word in the keyword...
if _and_search(index, word) == 0:
# The next keyword must be the first.
first = True
index = index + 1 # Advance the index
# I need to format the keywords as a list and instantiate the array of keywords as an empty array.
key_list, keywords = list(keys), []
# Split list into keyword/arg sets
_split_keyword_list()
# For each key/arg item in the list...
for keyword in keywords:
# Run the keyword with its arguments
if keyword[0].lower() != 'exit if':
BuiltIn().run_keyword(keyword[0], *keyword[1:])
elif Loops()._is_boolean_string(keyword[1]) and BuiltIn().run_keyword(keyword[0], *keyword[1:]):
return False
return True
@staticmethod
def _index_var_swap(loop_iteration, index_var, *keywords):
# Format the keywords as a list for iteration
keywords = list(keywords)
index = 0
# For every line in keywords
for line in keywords:
# Replace all instances of the index_var in the string with the loop iteration as a string
keywords[index] = str(line).replace(str(index_var), str(loop_iteration))
index = index + 1
return keywords
@staticmethod
def _deliminator_search(start, keyword, *keywords):
index = 0
while keyword != '\\' and keyword != '\\\\':
keyword = keywords[int(start) + index]
index = index + 1
return index
And the Robot Framework code that tests it:
*** Variables ***
${blue_squadron} = Blue
${gold_squadron} = Gold
${green_squadron} = Green
${red_squadron} = Red
*** Test Cases ***
Test For Loop IN RANGE
For Loop IN RANGE 0 1 INDEX0
... \\ For Loop IN RANGE 1 6 INDEX1
... \\ \\ {standing_by}= standing by
... \\ \\ Run Keyword If INDEX1 == 1 Log to Console This is ${red_squadron} Leader standing by
... \\ \\ Run Keyword Unless INDEX1 == 1 Log to Console ${red_squadron} INDEX1 {standing_by}
... \\ For Loop IN RANGE 1 6 INDEX2
... \\ \\ standing_by_2 = standing by
... \\ \\ Run Keyword If INDEX2 == 1 Log to Console This is ${gold_squadron} Leader standing by
... \\ \\ Run Keyword Unless INDEX2 == 1 Log to Console ${gold_squadron} INDEX2 standing_by_2
... \\ For Loop IN RANGE 1 6 INDEX3
... \\ \\ standing_by_3= Get Blue Squadron
... \\ \\ Run Keyword If INDEX3 == 1 Log to Console This is ${blue_squadron} Leader standing by
... \\ \\ Run Keyword Unless INDEX3 == 1 Log to Console ${blue_squadron} INDEX3 standing_by_3
... \\ For Loop IN RANGE 1 6 INDEX4
... \\ \\ standing_by_4 = Get Green Squadron null input
... \\ \\ Run Keyword If INDEX4 == 1 Log to Console This is ${green_squadron} Leader standing by
... \\ \\ Run Keyword Unless INDEX4 == 1 Log to Console ${green_squadron} INDEX4 standing_by_4
Test IN RANGE Edge Case 1 - Single Keyword with Single Argument
For Loop IN RANGE 0 1 INDEX0
... \\ Log to Console testlog
Test For Loop Exit
For Loop IN RANGE 0 3 INDEX0
... \\ Log to Console INDEX0
... \\ Exit If INDEX0 == 1
*** Keywords ***
Get Blue Squadron
[Return] standing by
Get Green Squadron
[Arguments] ${text}
[Return] standing by
