mirror of
https://github.com/kanaka/mal.git
synced 2024-09-11 13:55:55 +03:00
40 lines
1.2 KiB
Plaintext
40 lines
1.2 KiB
Plaintext
--- step3_env -----------------------------------
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import types, reader, printer, env
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READ(str): return reader.read_str(str)
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eval_ast(ast,env):
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switch type(ast):
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symbol: return env.get(ast)
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list,vector: return ast.map((x) -> EVAL(x,env))
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hash: return ast.map((k,v) -> list(k, EVAL(v,env)))
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_default_: return ast
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EVAL(ast,env):
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if not list?(ast): return eval_ast(ast, env)
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if empty?(ast): return ast
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switch ast[0]:
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'def!: return env.set(ast[1], EVAL(ast[2], env))
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'let*: let_env = ...; return EVAL(ast[2], let_env)
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_default_: f, args = eval_ast(ast, env)
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return apply(f, args)
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PRINT(exp): return printer.pr_str(exp)
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repl_env = new Env()
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rep(str): return PRINT(EVAL(READ(str),repl_env))
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repl_env.set('+, add_fn)
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...
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main loop:
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try: println(rep(readline("user> ")))
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catch e: println("Error: ", e)
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--- env module ----------------------------------
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class Env (outer=null)
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data = hash_map()
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set(k,v): return data.set(k,v)
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find(k): return data.has(k) ? this : (if outer ? find(outer) : null)
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get(k): return data.find(k).get(k) OR raise "'" + k + "' not found"
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