mirror of
https://github.com/kanaka/mal.git
synced 2024-09-11 13:55:55 +03:00
27 lines
744 B
Plaintext
27 lines
744 B
Plaintext
--- step2_eval ----------------------------------
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import types, reader, printer
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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 lookup(env, ast) OR raise "'" + ast + "' not found"
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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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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 = {'+: add_fn, ...}
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rep(str): return PRINT(EVAL(READ(str),repl_env))
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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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