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#!/usr/bin/env python
"""js.py - Repl-like toy to explore parsing of lines of JS.
See README.md for instructions.
"""
import argparse
import traceback
from .lexer import JSLexer
from .parser import JSParser
from jsparagus.lexer import SyntaxError
def interactive_input(lexer, prompt="js> "):
while True:
line = input(prompt)
lexer.write(line + "\n")
if lexer.can_close():
return lexer.close()
prompt = "..> "
def rpl():
"""Read-print loop."""
while True:
parser = JSLexer(JSParser(), filename="<stdin>")
try:
result = interactive_input(parser)
except EOFError:
print()
break
except SyntaxError:
traceback.print_exc(limit=0)
continue
print(result)
def main():
parser = argparse.ArgumentParser(description="Try out the JS parser.")
parser.add_argument('input_file', metavar='FILE', nargs='?',
help=".js file to parse")
options = parser.parse_args()
if options.input_file is not None:
with open(options.input_file) as f:
source = f.readlines()
lexer = JSLexer(JSParser())
for line in source:
print(line.rstrip())
lexer.write(line)
ast = lexer.close()
print(ast)
else:
rpl()
if __name__ == '__main__':
main()