mirror of
https://github.com/kanaka/mal.git
synced 2024-09-21 10:37:58 +03:00
131 lines
2.9 KiB
Julia
131 lines
2.9 KiB
Julia
module reader
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export read_str
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import types
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type Reader
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tokens
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position::Int64
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end
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function next(rdr::Reader)
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if rdr.position > length(rdr.tokens)
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return nothing
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end
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rdr.position += 1
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rdr.tokens[rdr.position-1]
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end
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function peek(rdr::Reader)
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if rdr.position > length(rdr.tokens)
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return nothing
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end
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rdr.tokens[rdr.position]
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end
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function tokenize(str)
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re = r"[\s,]*(~@|[\[\]{}()'`~^@]|\"(?:\\.|[^\\\"])*\"|;.*|[^\s\[\]{}('\"`,;)]*)"
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tokens = map((m) -> m.captures[1], eachmatch(re, str))
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filter((t) -> t != "" && t[1] != ';', tokens)
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end
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function read_atom(rdr)
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token = next(rdr)
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if ismatch(r"^-?[0-9]+$", token)
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parse(Int,token)
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elseif ismatch(r"^-?[0-9][0-9.]*$", token)
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float(token)
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elseif ismatch(r"^\".*\"$", token)
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replace(token[2:end-1], r"\\.", (r) -> get(Dict("\\n"=>"\n",
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"\\\""=>"\"",
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"\\\\"=>"\\"), r, r))
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elseif token[1] == ':'
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"\u029e$(token[2:end])"
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elseif token == "nil"
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nothing
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elseif token == "true"
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true
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elseif token == "false"
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false
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else
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symbol(token)
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end
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end
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function read_list(rdr, start="(", last=")")
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ast = Any[]
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token = next(rdr)
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if (token != start)
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error("expected '$(start)'")
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end
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while ((token = peek(rdr)) != last)
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if token == nothing
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error("expected '$(last)', got EOF")
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end
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push!(ast, read_form(rdr))
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end
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next(rdr)
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ast
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end
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function read_vector(rdr)
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lst = read_list(rdr, "[", "]")
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tuple(lst...)
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end
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function read_hash_map(rdr)
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lst = read_list(rdr, "{", "}")
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types.hash_map(lst...)
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end
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function read_form(rdr)
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token = peek(rdr)
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if token == "'"
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next(rdr)
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[[:quote]; Any[read_form(rdr)]]
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elseif token == "`"
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next(rdr)
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[[:quasiquote]; Any[read_form(rdr)]]
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elseif token == "~"
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next(rdr)
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[[:unquote]; Any[read_form(rdr)]]
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elseif token == "~@"
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next(rdr)
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[[symbol("splice-unquote")]; Any[read_form(rdr)]]
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elseif token == "^"
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next(rdr)
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meta = read_form(rdr)
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[[symbol("with-meta")]; Any[read_form(rdr)]; Any[meta]]
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elseif token == "@"
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next(rdr)
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[[symbol("deref")]; Any[read_form(rdr)]]
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elseif token == ")"
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error("unexpected ')'")
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elseif token == "("
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read_list(rdr)
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elseif token == "]"
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error("unexpected ']'")
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elseif token == "["
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read_vector(rdr)
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elseif token == "}"
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error("unexpected '}'")
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elseif token == "{"
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read_hash_map(rdr)
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else
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read_atom(rdr)
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end
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end
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function read_str(str)
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tokens = tokenize(str)
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if length(tokens) == 0
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return nothing
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end
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read_form(Reader(tokens, 1))
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end
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end
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