26 lines
553 B
Text
26 lines
553 B
Text
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iface HasEnv {
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env: Map<str, str>,
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}
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iface HasVal {
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val: str,
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}
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alias Ident = /([a-zA-Z][a-zA-Z0-9_]*)|(_[a-zA-Z0-9_]+)/
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node Expr : HasEnv + HasVal {
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"let" <name:Ident> "=" <val:Expr> "in" <body:Expr> => {
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body.env = self.env.with(name, val);
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self.val = body.val;
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}
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<name:Ident> => {
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// TODO: does env need to be referenced here?
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// TODO: how to check for unbound names ahead of time
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// (for self-implementation)
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self.val = self.env.lookup(name);
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}
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<string:StringLit> => {
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self.val = string;
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}
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}
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