Files
Nassi-Shneiderman-Diagramm-…/interpreter/interpret_source.py
2020-12-26 18:19:50 +01:00

103 lines
3.8 KiB
Python

import logging
import re
from typing import List, Tuple
from draw.Iinstruction import *
COMMENT_REGEX = r"""^//|^#|^COMMENT|^--"""
class JavaSyntaxError(Exception):
pass
class ScopeNotFoundException(Exception):
pass
def load_src(filepath: str) -> List[str]:
lines: List[str] = []
brace_open_count, brace_closed_count = 0,0
try:
with open(filepath, encoding="utf-8") as file:
for _line in file:
line = _line.strip().replace(' ', '')
if line and not re.match(COMMENT_REGEX, line):
lines.append(line)
if line.__contains__('{'):
brace_open_count += 1
if line.__contains__('}'):
brace_closed_count += 1
except:
raise FileNotFoundError(f"File {filepath} was not found!")
if brace_open_count != brace_closed_count:
raise JavaSyntaxError("Number of opened braces does not match number of closed ones. Program is ill-formed!")
return lines
def get_scope_start_offset(src: List[str], start_idx: int) -> int:
i = start_idx
while i < len(src):
line = src[i]
if line.__contains__("{"):
return i - start_idx + 1
i += 1
raise ScopeNotFoundException("Unable to find scope start. Is the program ill-formed?")
def get_instructions_in_scope(src: List[str], start_idx: int = 0) -> Tuple[List[Iinstruction], int]:
outer_scope: List[Iinstruction] = []
i = start_idx
while i < len(src):
line = src[i]
try:
if line.__contains__('}'): #We exited this scope, return it
return outer_scope, i
if line.startswith("while("):
logging.debug("Found while instruction in line: %i", i+1)
bracket_idx = line.rindex(')') # throws if while contruct is illformed
instruction_txt = line[6:bracket_idx]
brace_offset = get_scope_start_offset(src, i)
child_instructions, i = get_instructions_in_scope(src, i+brace_offset)
outer_scope.append(while_instruction_front(('while ' + instruction_txt), child_instructions))
elif line.startswith("if("):
logging.debug("Found if instruction in line: %i", i+1)
bracket_idx = line.rindex(')') # throws if the contruct is illformed
instruction_txt = line[3:bracket_idx]
brace_offset = get_scope_start_offset(src, i)
true_instructions, i = get_instructions_in_scope(src, i+brace_offset)
false_instructions = None
if src[i].__contains__("else"): #if there is an else statement, check it
false_instructions, i = get_instructions_in_scope(src, i+2)
outer_scope.append(if_instruction(instruction_txt, true_instructions, false_instructions))
elif line.startswith("do{"):
#construct:
#do{
#...
#}while(...);
logging.debug("Found start of do-while instruction in line: %i", i)
brace_offset = get_scope_start_offset(src, i)
child_instructions, i = get_instructions_in_scope(src, i+brace_offset)
end_line = src[i]
bracket_idx = end_line.rindex(");")
instruction_txt = end_line[7: bracket_idx]
outer_scope.append(while_instruction_back(('do while' + instruction_txt), child_instructions))
else:
logging.debug("Found generic instruction in line: %i", i+1)
outer_scope.append(generic_instruction(line))
except:
logging.error("Encountered error in line: %i", i)
raise # rethrow
i += 1
return outer_scope, 0