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Copy pathstatements.py
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Copy pathstatements.py
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1556 lines (1433 loc) · 56.2 KB
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"""
PC-BASIC - statements.py
Statement parser
(c) 2013--2023 Rob Hagemans
This file is released under the GNU GPL version 3 or later.
"""
import logging
import struct
from functools import partial
from ...compat import iterchar
from ..base import error
from ..base import tokens as tk
from ..base.tokens import DIGITS, LETTERS
from .. import values
from . import expressions
from . import userfunctions
class Parser(object):
"""BASIC statement parser."""
def __init__(self, values, memory, syntax):
"""Initialise statement context."""
# re-execute current statement after Break
self.redo_on_break = False
# expression parser
self.expression_parser = expressions.ExpressionParser(values, memory)
self.user_functions = self.expression_parser.user_functions
# syntax: advanced, pcjr, tandy
self._syntax = syntax
# initialise syntax parser tables
self._init_syntax()
def __getstate__(self):
"""Pickle."""
pickle_dict = self.__dict__.copy()
# can't be pickled
pickle_dict['_simple'] = None
pickle_dict['_complex'] = None
pickle_dict['_callbacks'] = None
return pickle_dict
def __setstate__(self, pickle_dict):
"""Unpickle."""
self.__dict__.update(pickle_dict)
self._init_syntax()
def init_callbacks(self, session):
"""Assign statement and function callbacks."""
self.init_statements(session)
self.expression_parser.init_functions(session)
def parse_statement(self, ins):
"""Parse and execute a single statement."""
# read keyword token or one byte
ins.skip_blank()
c = ins.read_keyword_token()
if c in self._simple:
parse_args = self._simple[c]
elif c in self._complex:
stat_dict = self._complex[c]
ins.skip_blank()
selector = ins.read_keyword_token()
ins.seek(-len(selector), 1)
if selector not in stat_dict.keys():
selector = None
else:
c += selector
parse_args = stat_dict[selector]
else:
ins.seek(-len(c), 1)
if c in set(iterchar(LETTERS)):
# implicit LET
c = tk.LET
parse_args = self._simple[tk.LET]
else:
ins.require_end()
return
self._callbacks[c](parse_args(ins))
# end-of-statement is checked at start of next statement in interpreter loop
def parse_name(self, ins):
"""Get scalar part of variable name from token stream."""
name = ins.read_name()
# must not be empty
error.throw_if(not name, error.STX)
# append sigil, if missing
return name
def parse_expression(self, ins, allow_empty=False):
"""Compute the value of the expression at the current code pointer."""
if allow_empty and ins.skip_blank() in tk.END_EXPRESSION:
return None
self.redo_on_break = True
val = self.expression_parser.parse_expression(ins)
self.redo_on_break = False
return val
###########################################################################
def _init_syntax(self):
"""Initialise syntax parsers."""
self._simple = {
tk.DATA: self._skip_statement,
tk.COMMON: self._skip_statement,
tk.REM: self._skip_line,
tk.ELSE: self._skip_line,
tk.CONT: self._parse_nothing,
tk.TRON: self._parse_nothing,
tk.TROFF: self._parse_nothing,
tk.WHILE: self._parse_nothing,
tk.RESET: self._parse_end,
tk.END: self._parse_end,
tk.STOP: self._parse_end,
tk.NEW: self._parse_end,
tk.WEND: self._parse_end,
tk.SYSTEM: self._parse_end,
tk.FOR: self._parse_for,
tk.NEXT: self._parse_next,
tk.INPUT: self._parse_input,
tk.DIM: self._parse_var_list,
tk.READ: self._parse_var_list,
tk.LET: self._parse_let,
tk.GOTO: self._parse_single_line_number,
tk.RUN: self._parse_run,
tk.IF: self._parse_if,
tk.RESTORE: self._parse_restore,
tk.GOSUB: self._parse_single_line_number,
tk.RETURN: self._parse_optional_line_number,
tk.PRINT: partial(self._parse_print, parse_file=True),
tk.CLEAR: self._parse_clear,
tk.LIST: self._parse_list,
tk.WAIT: self._parse_wait,
tk.POKE: self._parse_two_args,
tk.OUT: self._parse_two_args,
tk.LPRINT: partial(self._parse_print, parse_file=False),
tk.LLIST: self._parse_delete_llist,
tk.WIDTH: self._parse_width,
tk.SWAP: self._parse_swap,
tk.ERASE: self._parse_erase,
tk.EDIT: self._parse_edit,
tk.ERROR: self._parse_single_arg,
tk.RESUME: self._parse_resume,
tk.DELETE: self._parse_delete_llist,
tk.AUTO: self._parse_auto,
tk.RENUM: self._parse_renum,
tk.DEFSTR: self._parse_deftype,
tk.DEFINT: self._parse_deftype,
tk.DEFSNG: self._parse_deftype,
tk.DEFDBL: self._parse_deftype,
tk.CALL: self._parse_call,
tk.CALLS: self._parse_call,
tk.WRITE: self._parse_write,
tk.OPTION: self._parse_option_base,
tk.RANDOMIZE: self._parse_optional_arg,
tk.OPEN: self._parse_open,
tk.CLOSE: self._parse_close,
tk.LOAD: self._parse_load,
tk.MERGE: self._parse_single_arg_no_end,
tk.SAVE: self._parse_save,
tk.COLOR: self._parse_color,
tk.CLS: self._parse_cls,
tk.MOTOR: self._parse_optional_arg,
tk.BSAVE: self._parse_bsave,
tk.BLOAD: self._parse_bload,
tk.SOUND: self._parse_sound,
tk.BEEP: self._parse_beep,
tk.PSET: self._parse_pset_preset,
tk.PRESET: self._parse_pset_preset,
tk.SCREEN: self._parse_screen,
tk.LOCATE: self._parse_locate,
tk.FILES: self._parse_optional_arg_no_end,
tk.FIELD: self._parse_field,
tk.NAME: self._parse_name,
tk.LSET: self._parse_let,
tk.RSET: self._parse_let,
tk.KILL: self._parse_single_arg_no_end,
tk.CHAIN: self._parse_chain,
tk.DATE: self._parse_time_date,
tk.TIME: self._parse_time_date,
tk.PAINT: self._parse_paint,
tk.COM: self._parse_com_command,
tk.CIRCLE: self._parse_circle,
tk.DRAW: self._parse_single_arg,
tk.TIMER: self._parse_event_command,
tk.IOCTL: self._parse_ioctl,
tk.CHDIR: self._parse_single_arg_no_end,
tk.MKDIR: self._parse_single_arg_no_end,
tk.RMDIR: self._parse_single_arg_no_end,
tk.SHELL: self._parse_optional_arg_no_end,
tk.ENVIRON: self._parse_single_arg_no_end,
tk.WINDOW: self._parse_window,
tk.LCOPY: self._parse_optional_arg,
tk.PCOPY: self._parse_pcopy,
tk.LOCK: self._parse_lock_unlock,
tk.UNLOCK: self._parse_lock_unlock,
tk.MID: self._parse_mid,
tk.PEN: self._parse_event_command,
b'_': self._parse_call_extension,
}
if self._syntax in ('pcjr', 'tandy'):
self._simple.update({
tk.TERM: self._parse_end,
tk.NOISE: self._parse_noise,
})
self._complex = {
tk.ON: {
tk.ERROR: self._parse_on_error_goto,
tk.KEY: self._parse_on_event,
tk.PEN: self._parse_on_event,
tk.TIMER: self._parse_on_event,
tk.PLAY: self._parse_on_event,
tk.COM: self._parse_on_event,
tk.STRIG: self._parse_on_event,
None: self._parse_on_jump,
},
tk.DEF: {
tk.FN: self._parse_def_fn,
tk.USR: self._parse_def_usr,
None: self._parse_def_seg,
},
tk.LINE: {
tk.INPUT: self._parse_line_input,
None: self._parse_line,
},
tk.KEY: {
tk.ON: self._parse_key_macro,
tk.OFF: self._parse_key_macro,
tk.LIST: self._parse_key_macro,
b'(': self._parse_com_command,
None: self._parse_two_args,
},
tk.PUT: {
b'(': self._parse_put_graph,
None: self._parse_put_get_file,
},
tk.GET: {
b'(': self._parse_get_graph,
None: self._parse_put_get_file,
},
tk.PLAY: {
tk.ON: self._parse_event_command,
tk.OFF: self._parse_event_command,
tk.STOP: self._parse_event_command,
None: self._parse_play,
},
tk.VIEW: {
tk.PRINT: self._parse_view_print,
None: self._parse_view,
},
tk.PALETTE: {
tk.USING: self._parse_palette_using,
None: self._parse_palette,
},
tk.STRIG: {
tk.ON: self._parse_strig_switch,
tk.OFF: self._parse_strig_switch,
None: self._parse_com_command,
},
}
def init_statements(self, session):
"""Initialise statement callbacks."""
self._callbacks = {
tk.DATA: list,
tk.COMMON: list,
tk.REM: list,
tk.ELSE: list,
tk.CONT: session.interpreter.cont_,
tk.TRON: session.interpreter.tron_,
tk.TROFF: session.interpreter.troff_,
tk.WHILE: session.interpreter.while_,
tk.RESET: session.files.reset_,
tk.END: session.end_,
tk.STOP: session.interpreter.stop_,
tk.NEW: session.new_,
tk.WEND: session.interpreter.wend_,
tk.SYSTEM: session.system_,
tk.FOR: session.interpreter.for_,
tk.NEXT: session.interpreter.next_,
tk.INPUT: session.input_,
tk.DIM: session.memory.arrays.dim_,
tk.READ: session.interpreter.read_,
tk.LET: session.memory.let_,
tk.GOTO: session.interpreter.goto_,
tk.RUN: session.run_,
tk.IF: session.interpreter.if_,
tk.RESTORE: session.interpreter.restore_,
tk.GOSUB: session.interpreter.gosub_,
tk.RETURN: session.interpreter.return_,
tk.PRINT: session.files.print_,
tk.CLEAR: session.clear_,
tk.LIST: session.list_,
tk.WAIT: session.machine.wait_,
tk.POKE: session.all_memory.poke_,
tk.OUT: session.machine.out_,
tk.LPRINT: session.files.lprint_,
tk.LLIST: session.interpreter.llist_,
tk.WIDTH: session.files.width_,
tk.SWAP: session.memory.swap_,
tk.ERASE: session.memory.arrays.erase_,
tk.EDIT: session.edit_,
tk.ERROR: session.interpreter.error_,
tk.RESUME: session.interpreter.resume_,
tk.DELETE: session.delete_,
tk.AUTO: session.auto_,
tk.RENUM: session.interpreter.renum_,
tk.DEFSTR: session.memory.defstr_,
tk.DEFINT: session.memory.defint_,
tk.DEFSNG: session.memory.defsng_,
tk.DEFDBL: session.memory.defdbl_,
tk.CALL: session.all_memory.call_,
tk.CALLS: session.all_memory.call_,
tk.WRITE: session.files.write_,
tk.OPTION: session.memory.arrays.option_base_,
tk.RANDOMIZE: session.randomize_,
tk.OPEN: session.files.open_,
tk.CLOSE: session.files.close_,
tk.LOAD: session.load_,
tk.MERGE: session.merge_,
tk.SAVE: session.save_,
tk.COLOR: session.display.color_,
tk.CLS: session.display.cls_,
tk.MOTOR: session.files.motor_,
tk.BSAVE: session.all_memory.bsave_,
tk.BLOAD: session.all_memory.bload_,
tk.SOUND: session.sound.sound_,
tk.BEEP: session.sound.beep_,
tk.PSET: session.graphics.pset_,
tk.PRESET: session.graphics.preset_,
tk.SCREEN: session.display.screen_,
tk.LOCATE: session.text_screen.locate_,
tk.FILES: session.files.files_,
tk.FIELD: session.files.field_,
tk.NAME: session.files.name_,
tk.LSET: session.memory.lset_,
tk.RSET: session.memory.rset_,
tk.KILL: session.files.kill_,
tk.CHAIN: session.chain_,
tk.DATE: session.clock.date_,
tk.TIME: session.clock.time_,
tk.PAINT: session.graphics.paint_,
tk.COM: session.basic_events.com_,
tk.CIRCLE: session.graphics.circle_,
tk.DRAW: session.graphics.draw_,
tk.TIMER: session.basic_events.timer_,
tk.IOCTL: session.files.ioctl_statement_,
tk.CHDIR: session.files.chdir_,
tk.MKDIR: session.files.mkdir_,
tk.RMDIR: session.files.rmdir_,
tk.SHELL: session.shell_,
tk.ENVIRON: session.environment.environ_statement_,
tk.WINDOW: session.graphics.window_,
tk.LCOPY: session.files.lcopy_,
tk.PCOPY: session.display.pcopy_,
tk.LOCK: session.files.lock_,
tk.UNLOCK: session.files.unlock_,
tk.MID: session.memory.mid_,
tk.PEN: session.basic_events.pen_,
tk.TERM: session.term_,
tk.NOISE: session.sound.noise_,
tk.ON + tk.ERROR: session.interpreter.on_error_goto_,
tk.ON + tk.KEY: session.basic_events.on_event_gosub_,
tk.ON + tk.PEN: session.basic_events.on_event_gosub_,
tk.ON + tk.TIMER: session.basic_events.on_event_gosub_,
tk.ON + tk.PLAY: session.basic_events.on_event_gosub_,
tk.ON + tk.COM: session.basic_events.on_event_gosub_,
tk.ON + tk.STRIG: session.basic_events.on_event_gosub_,
tk.ON: session.interpreter.on_jump_,
tk.DEF + tk.FN: session.interpreter.def_fn_,
tk.DEF + tk.USR: session.all_memory.def_usr_,
tk.DEF: session.all_memory.def_seg_,
tk.LINE + tk.INPUT: session.line_input_,
tk.LINE: session.graphics.line_,
tk.KEY + tk.ON: session.console.key_,
tk.KEY + tk.OFF: session.console.key_,
tk.KEY + tk.LIST: session.console.key_,
tk.KEY + b'(': session.basic_events.key_,
tk.KEY: session.key_,
tk.PUT + b'(': session.graphics.put_,
tk.PUT: session.files.put_,
tk.GET + b'(': session.graphics.get_,
tk.GET: session.files.get_,
tk.PLAY + tk.ON: session.basic_events.play_,
tk.PLAY + tk.OFF: session.basic_events.play_,
tk.PLAY + tk.STOP: session.basic_events.play_,
tk.PLAY: session.sound.play_,
tk.VIEW + tk.PRINT: session.text_screen.view_print_,
tk.VIEW: session.graphics.view_,
tk.PALETTE + tk.USING: session.display.palette_using_,
tk.PALETTE: session.display.palette_,
tk.STRIG + tk.ON: session.stick.strig_statement_,
tk.STRIG + tk.OFF: session.stick.strig_statement_,
tk.STRIG: session.basic_events.strig_,
b'_': session.extensions.call_as_statement,
}
###########################################################################
# auxiliary functions
def _parse_bracket(self, ins):
"""Compute the value of the bracketed expression."""
ins.require_read((b'(',))
# we'll get a Syntax error, not a Missing operand, if we close with )
val = self.parse_expression(ins)
ins.require_read((b')',))
return val
def _parse_variable(self, ins):
"""Helper function: parse a scalar or array element."""
name = ins.read_name()
error.throw_if(not name, error.STX)
self.redo_on_break = True
indices = self.expression_parser.parse_indices(ins)
self.redo_on_break = False
return name, indices
def _parse_jumpnum(self, ins):
"""Parses a line number pointer as in GOTO, GOSUB, LIST, RENUM, EDIT, etc."""
ins.require_read((tk.T_UINT,))
token = ins.read(2)
assert len(token) == 2, 'Bytecode truncated in line number pointer'
return struct.unpack('<H', token)[0]
def _parse_optional_jumpnum(self, ins):
"""Parses a line number pointer as in GOTO, GOSUB, LIST, RENUM, EDIT, etc."""
# no line number
if ins.skip_blank() != tk.T_UINT:
return None
return self._parse_jumpnum(ins)
def _parse_line_range(self, ins):
"""Parse a line number range as in LIST, DELETE."""
from_line = self._parse_jumpnum_or_dot(ins, allow_empty=True)
if ins.skip_blank_read_if((tk.O_MINUS,)):
to_line = self._parse_jumpnum_or_dot(ins, allow_empty=True)
else:
to_line = from_line
return (from_line, to_line)
def _parse_jumpnum_or_dot(self, ins, allow_empty=False, err=error.STX):
"""Parse jump target; returns int, None or '.'"""
c = ins.skip_blank_read()
if c == tk.T_UINT:
token = ins.read(2)
assert len(token) == 2, 'bytecode truncated in line number pointer'
return struct.unpack('<H', token)[0]
elif c == b'.':
return b'.'
else:
if allow_empty:
ins.seek(-len(c), 1)
return None
raise error.BASICError(err)
###########################################################################
# no arguments
def _parse_nothing(self, ins):
"""Parse nothing."""
# e.g. TRON LAH raises error but TRON will have been executed
return
yield # pragma: no cover
def _parse_end(self, ins):
"""Parse end-of-statement before executing argumentless statement."""
# e.g. SYSTEM LAH does not execute
ins.require_end()
# empty generator
return
yield # pragma: no cover
def _skip_line(self, ins):
"""Ignore the rest of the line."""
ins.skip_to(tk.END_LINE)
return
yield # pragma: no cover
def _skip_statement(self, ins):
"""Ignore rest of statement."""
ins.skip_to(tk.END_STATEMENT)
return
yield # pragma: no cover
###########################################################################
# single argument
def _parse_optional_arg(self, ins):
"""Parse statement with one optional argument."""
yield self.parse_expression(ins, allow_empty=True)
ins.require_end()
def _parse_optional_arg_no_end(self, ins):
"""Parse statement with one optional argument."""
yield self.parse_expression(ins, allow_empty=True)
def _parse_single_arg(self, ins):
"""Parse statement with one mandatory argument."""
yield self.parse_expression(ins)
ins.require_end()
def _parse_single_arg_no_end(self, ins):
"""Parse statement with one mandatory argument."""
yield self.parse_expression(ins)
def _parse_single_line_number(self, ins):
"""Parse statement with single line number argument."""
yield self._parse_jumpnum(ins)
def _parse_optional_line_number(self, ins):
"""Parse statement with optional line number argument."""
jumpnum = None
if ins.skip_blank() == tk.T_UINT:
jumpnum = self._parse_jumpnum(ins)
yield jumpnum
###########################################################################
# two arguments
def _parse_two_args(self, ins):
"""Parse POKE or OUT syntax."""
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
###########################################################################
# flow-control statements
def _parse_run(self, ins):
"""Parse RUN syntax."""
c = ins.skip_blank()
if c == tk.T_UINT:
# parse line number and ignore rest of line
yield self._parse_jumpnum(ins)
elif c not in tk.END_STATEMENT:
yield None
yield self.parse_expression(ins)
if ins.skip_blank_read_if((b',',)):
ins.require_read((b'R',))
yield True
else:
yield False
else:
yield None
def _parse_resume(self, ins):
"""Parse RESUME syntax."""
c = ins.skip_blank()
if c == tk.NEXT:
yield ins.read(1)
elif c in tk.END_STATEMENT:
yield None
else:
yield self._parse_jumpnum(ins)
ins.require_end()
def _parse_on_error_goto(self, ins):
"""Parse ON ERROR GOTO syntax."""
ins.require_read((tk.ERROR,))
ins.require_read((tk.GOTO,))
yield self._parse_jumpnum(ins)
###########################################################################
# event statements
def _parse_event_command(self, ins):
"""Parse PEN, PLAY or TIMER syntax."""
yield ins.require_read((tk.ON, tk.OFF, tk.STOP))
def _parse_com_command(self, ins):
"""Parse KEY, COM or STRIG syntax."""
yield self._parse_bracket(ins)
yield ins.require_read((tk.ON, tk.OFF, tk.STOP))
def _parse_strig_switch(self, ins):
"""Parse STRIG ON/OFF syntax."""
yield ins.require_read((tk.ON, tk.OFF))
def _parse_on_event(self, ins):
"""Helper function for ON event trap definitions."""
# token is known to be in (tk.PEN, tk.KEY, tk.TIMER, tk.PLAY, tk.COM, tk.STRIG)
# before we call this generator
token = ins.read_keyword_token()
yield token
if token != tk.PEN:
yield self._parse_bracket(ins)
else:
yield None
ins.require_read((tk.GOSUB,))
yield self._parse_jumpnum(ins)
ins.require_end()
###########################################################################
# sound statements
def _parse_beep(self, ins):
"""Parse BEEP syntax."""
if self._syntax in ('pcjr', 'tandy'):
# Tandy/PCjr BEEP ON, OFF
yield ins.skip_blank_read_if((tk.ON, tk.OFF))
else:
yield None
# if a syntax error happens, we still beeped.
def _parse_noise(self, ins):
"""Parse NOISE syntax (Tandy/PCjr)."""
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
ins.require_end()
def _parse_sound(self, ins):
"""Parse SOUND syntax."""
command = None
if self._syntax in ('pcjr', 'tandy'):
# Tandy/PCjr SOUND ON, OFF
command = ins.skip_blank_read_if((tk.ON, tk.OFF))
if command:
yield command
else:
yield self.parse_expression(ins)
ins.require_read((b',',))
dur = self.parse_expression(ins)
yield dur
# only look for args 3 and 4 if duration is > 0;
# otherwise those args are a syntax error (on tandy)
if (dur.sign() == 1) and ins.skip_blank_read_if((b',',)) and self._syntax in ('pcjr', 'tandy'):
yield self.parse_expression(ins, allow_empty=True)
if ins.skip_blank_read_if((b',',)):
yield self.parse_expression(ins)
else:
yield None
else:
yield None
yield None
ins.require_end()
def _parse_play(self, ins):
"""Parse PLAY (music) syntax."""
if self._syntax in ('pcjr', 'tandy'):
for _ in range(3):
last = self.parse_expression(ins, allow_empty=True)
yield last
if not ins.skip_blank_read_if((b',',)):
break
else:
raise error.BASICError(error.STX)
if last is None:
raise error.BASICError(error.MISSING_OPERAND)
ins.require_end()
else:
yield self.parse_expression(ins, allow_empty=True)
ins.require_end(err=error.IFC)
###########################################################################
# memory and machine port statements
def _parse_def_seg(self, ins):
"""Parse DEF SEG syntax."""
# must be uppercase in tokenised form, otherwise syntax error
ins.require_read((tk.W_SEG,))
if ins.skip_blank_read_if((tk.O_EQ,)):
yield self.parse_expression(ins)
else:
yield None
def _parse_def_usr(self, ins):
"""Parse DEF USR syntax."""
ins.require_read((tk.USR,))
yield ins.skip_blank_read_if(tk.DIGIT)
ins.require_read((tk.O_EQ,))
yield self.parse_expression(ins)
def _parse_bload(self, ins):
"""Parse BLOAD syntax."""
yield self.parse_expression(ins)
if ins.skip_blank_read_if((b',',)):
yield self.parse_expression(ins)
else:
yield None
ins.require_end()
def _parse_bsave(self, ins):
"""Parse BSAVE syntax."""
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
ins.require_end()
def _parse_call(self, ins):
"""Parse CALL and CALLS syntax."""
yield self.parse_name(ins)
if ins.skip_blank_read_if((b'(',)):
while True:
yield self._parse_variable(ins)
if not ins.skip_blank_read_if((b',',)):
break
ins.require_read((b')',))
ins.require_end()
def _parse_wait(self, ins):
"""Parse WAIT syntax."""
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
if ins.skip_blank_read_if((b',',)):
yield self.parse_expression(ins)
else:
yield None
ins.require_end()
def _parse_call_extension(self, ins):
"""Parse extension statement."""
yield ins.read_name()
while True:
yield self.parse_expression(ins, allow_empty=True)
if not ins.skip_blank_read_if((b',',)):
break
###########################################################################
# disk statements
def _parse_name(self, ins):
"""Parse NAME syntax."""
yield self.parse_expression(ins)
# AS is not a tokenised word
ins.require_read((tk.W_AS,))
yield self.parse_expression(ins)
###########################################################################
# clock statements
def _parse_time_date(self, ins):
"""Parse TIME$ or DATE$ syntax."""
ins.require_read((tk.O_EQ,))
yield self.parse_expression(ins)
ins.require_end()
##########################################################
# code statements
def _parse_delete_llist(self, ins):
"""Parse DELETE syntax."""
yield self._parse_line_range(ins)
ins.require_end()
def _parse_edit(self, ins):
"""Parse EDIT syntax."""
if ins.skip_blank() not in tk.END_STATEMENT:
yield self._parse_jumpnum_or_dot(ins, err=error.IFC)
else:
yield None
ins.require_end(err=error.IFC)
def _parse_auto(self, ins):
"""Parse AUTO syntax."""
yield self._parse_jumpnum_or_dot(ins, allow_empty=True)
if ins.skip_blank_read_if((b',',)):
inc = self._parse_optional_jumpnum(ins)
if inc is None:
raise error.BASICError(error.IFC)
else:
yield inc
else:
yield None
ins.require_end()
def _parse_save(self, ins):
"""Parse SAVE syntax."""
yield self.parse_expression(ins)
if ins.skip_blank_read_if((b',',)):
yield ins.require_read((b'A', b'a', b'P', b'p'))
else:
yield None
ins.require_end()
def _parse_list(self, ins):
"""Parse LIST syntax."""
yield self._parse_line_range(ins)
if ins.skip_blank_read_if((b',',)):
yield self.parse_expression(ins)
# ignore everything after file spec
ins.skip_to(tk.END_LINE)
else:
yield None
ins.require_end()
def _parse_load(self, ins):
"""Parse LOAD syntax."""
yield self.parse_expression(ins)
if ins.skip_blank_read_if((b',',)):
yield ins.require_read((b'R', b'r'))
else:
yield None
ins.require_end()
def _parse_renum(self, ins):
"""Parse RENUM syntax."""
new, old, step = None, None, None
if ins.skip_blank() not in tk.END_STATEMENT:
new = self._parse_jumpnum_or_dot(ins, allow_empty=True)
if ins.skip_blank_read_if((b',',)):
old = self._parse_jumpnum_or_dot(ins, allow_empty=True)
if ins.skip_blank_read_if((b',',)):
# the number not optional at all if a comma is given
# but we need to control the error type
step = self._parse_optional_jumpnum(ins)
# negative numbers leave us before the end and raise STX
ins.require_end()
# empty afer comma raises IFC
if step is None:
raise error.BASICError(error.IFC)
# we need require_end in both places to get correct error sequencing
ins.require_end()
for n in (new, old, step):
yield n
def _parse_chain(self, ins):
"""Parse CHAIN syntax."""
yield ins.skip_blank_read_if((tk.MERGE,)) is not None
yield self.parse_expression(ins)
jumpnum, common_all, delete_range = None, False, True
if ins.skip_blank_read_if((b',',)):
# check for an expression that indicates a line in the other program.
# This is not stored as a jumpnum (to avoid RENUM)
jumpnum = self.parse_expression(ins, allow_empty=True)
if ins.skip_blank_read_if((b',',)):
common_all = ins.skip_blank_read_if((tk.W_ALL,), 3)
if common_all:
# CHAIN "file", , ALL, DELETE
delete_range = ins.skip_blank_read_if((b',',))
# CHAIN "file", , DELETE
yield jumpnum
yield common_all
if delete_range and ins.skip_blank_read_if((tk.DELETE,)):
from_line = self._parse_optional_jumpnum(ins)
if ins.skip_blank_read_if((tk.O_MINUS,)):
to_line = self._parse_optional_jumpnum(ins)
else:
to_line = from_line
error.throw_if(not to_line)
delete_lines = (from_line, to_line)
# ignore rest if preceded by comma
if ins.skip_blank_read_if((b',',)):
ins.skip_to(tk.END_STATEMENT)
yield delete_lines
else:
yield None
ins.require_end()
###########################################################################
# file statements
def _parse_open(self, ins):
"""Parse OPEN syntax."""
yield self.parse_expression(ins)
first_syntax = ins.skip_blank_read_if((b',',))
yield first_syntax
if first_syntax:
args = self._parse_open_first(ins)
else:
args = self._parse_open_second(ins)
for a in args:
yield a
def _parse_open_first(self, ins):
"""Parse OPEN first ('old') syntax."""
ins.skip_blank_read_if((b'#',))
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
if ins.skip_blank_read_if((b',',)):
yield self.parse_expression(ins)
else:
yield None
def _parse_open_second(self, ins):
"""Parse OPEN second ('new') syntax."""
# mode clause
if ins.skip_blank_read_if((tk.FOR,)):
# read mode word
if ins.skip_blank_read_if((tk.INPUT,)):
yield b'I'
else:
mode_dict = {tk.W_OUTPUT: b'O', tk.W_RANDOM: b'R', tk.W_APPEND: b'A'}
word = ins.skip_blank_read_if(mode_dict, 6)
if word is not None:
yield mode_dict[word]
else:
raise error.BASICError(error.STX)
else:
yield None
# ACCESS clause
if ins.skip_blank_read_if((tk.W_ACCESS,), 6):
yield self._parse_read_write(ins)
else:
yield None
# LOCK clause
if ins.skip_blank_read_if((tk.LOCK,), 2):
yield self._parse_read_write(ins)
else:
yield ins.skip_blank_read_if((tk.W_SHARED,), 6)
# AS file number clause
ins.require_read((tk.W_AS,))
ins.skip_blank_read_if((b'#',))
yield self.parse_expression(ins)
# LEN clause
if ins.skip_blank_read_if((tk.LEN,), 2):
ins.require_read((tk.O_EQ,))
yield self.parse_expression(ins)
else:
yield None
def _parse_read_write(self, ins):
"""Parse access mode for OPEN."""
d = ins.skip_blank_read_if((tk.READ, tk.WRITE))
if d == tk.WRITE:
return b'W'
elif d == tk.READ:
return b'RW' if ins.skip_blank_read_if((tk.WRITE,)) else b'R'
raise error.BASICError(error.STX)
def _parse_close(self, ins):
"""Parse CLOSE syntax."""
if ins.skip_blank() not in tk.END_STATEMENT:
while True:
# if an error occurs, the files parsed before are closed anyway
ins.skip_blank_read_if((b'#',))
yield self.parse_expression(ins)
if not ins.skip_blank_read_if((b',',)):
break
def _parse_field(self, ins):
"""Parse FIELD syntax."""
ins.skip_blank_read_if((b'#',))
yield self.parse_expression(ins)
if ins.skip_blank_read_if((b',',)):
while True:
yield self.parse_expression(ins)
ins.require_read((tk.W_AS,), err=error.IFC)
yield self._parse_variable(ins)
if not ins.skip_blank_read_if((b',',)):
break
def _parse_lock_unlock(self, ins):
"""Parse LOCK or UNLOCK syntax."""
ins.skip_blank_read_if((b'#',))
yield self.parse_expression(ins)
if not ins.skip_blank_read_if((b',',)):
ins.require_end()
yield None
yield None
else:
expr = self.parse_expression(ins, allow_empty=True)
yield expr
if ins.skip_blank_read_if((tk.TO,)):
yield self.parse_expression(ins)
elif expr is not None:
yield None
else:
raise error.BASICError(error.MISSING_OPERAND)
def _parse_ioctl(self, ins):
"""Parse IOCTL syntax."""
ins.skip_blank_read_if((b'#',))
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
def _parse_put_get_file(self, ins):
"""Parse PUT and GET syntax."""
ins.skip_blank_read_if((b'#',))
yield self.parse_expression(ins)
if ins.skip_blank_read_if((b',',)):
yield self.parse_expression(ins)
else:
yield None
###########################################################################
# graphics statements
def _parse_pair(self, ins):
"""Parse coordinate pair."""
ins.require_read((b'(',))
yield self.parse_expression(ins)
ins.require_read((b',',))
yield self.parse_expression(ins)
ins.require_read((b')',))
def _parse_pset_preset(self, ins):
"""Parse PSET and PRESET syntax."""
yield ins.skip_blank_read_if((tk.STEP,))
for c in self._parse_pair(ins):