84 lines
2.5 KiB
Python
84 lines
2.5 KiB
Python
import tango.utils as utils
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from tango.value import TangoExpr, TangoIdent
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from tango.scope import RootTangoScope, ChildTangoScope
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from tango.parser import StringReader, TangoParser
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class TangoVM:
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def __init__(self):
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self.root_scope = RootTangoScope()
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def eval_string(self, s):
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r = StringReader(s)
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p = TangoParser(r)
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e = p.parse()
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return self.eval(e)
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def eval(self, expr):
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if utils.is_expr(expr):
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return self.eval_in_scope(self.root_scope, expr)
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else:
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raise ValueError('Root was not Tango Expression')
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def def_builtin(self, ident, builtin):
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if isinstance(ident, str):
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ident = TangoIdent(ident)
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if utils.is_ident(ident):
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self.root_scope.set_def(ident, builtin)
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else:
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raise ValueError('Not ident')
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def eval_in_scope(self, scope, val):
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if utils.is_expr(val):
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if val.is_unit:
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return None
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elif val.is_block:
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return self._do_block(scope, val)
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elif val.is_call:
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return self._do_call(scope, val)
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if utils.is_ident(val):
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return scope.get_def(val)
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return val
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def multi_eval_in_scope(self, scope, vals):
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return [self.eval_in_scope(scope, val) for val in vals]
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def _do_eval_child(self, scope, expr, args = TangoExpr()):
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child_scope = ChildTangoScope(scope)
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child_scope.set_def('$', args)
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return self.eval_in_scope(child_scope, expr)
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def _do_block(self, scope, block_expr):
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for expr in block_expr:
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res = self.eval_in_scope(scope, expr)
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return res
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def _do_call(self, scope, call_expr):
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fn_ident, *fn_args = call_expr
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fn_args = TangoExpr(fn_args)
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fn_body = scope.get_def(fn_ident)
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if fn_body is None:
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TangoVM._rt_error('ident `{}` is undefined'.format(fn_ident))
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if utils.is_callable(fn_body):
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return fn_body(self, scope, *fn_args)
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if utils.is_expr(fn_body):
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if fn_body.is_unit:
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return None
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if fn_body.is_block:
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return self._do_eval_child(scope, fn_body, fn_args)
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elif fn_body.is_call:
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fn_body = self._do_call(scope, fn_body)
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return self._do_eval_child(scope, fn_body, fn_args)
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TangoVM._rt_error('fatal error')
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@staticmethod
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def _rt_error(msg):
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raise RuntimeError(msg)
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