mirror of
https://github.com/kanaka/mal.git
synced 2024-09-20 01:57:09 +03:00
3faa513e83
- Use re from standard library instead of nre - Allow make -j4 - Rebuild binaries after source changed
116 lines
2.9 KiB
Nim
116 lines
2.9 KiB
Nim
import re, strutils, sequtils, types
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let
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tokenRE = re"""[\s,]*(~@|[\[\]{}()'`~^@]|"(?:\\.|[^\\"])*"|;.*|[^\s\[\]{}('"`,;)]*)"""
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intRE = re"-?[0-9]+$"
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type
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Blank* = object of Exception
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Reader = object
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tokens: seq[string]
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position: int
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proc next(r: var Reader): string =
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if r.position >= r.tokens.len:
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result = nil
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else:
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result = r.tokens[r.position]
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inc r.position
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proc peek(r: Reader): string =
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if r.position >= r.tokens.len: nil
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else: r.tokens[r.position]
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proc tokenize(str: string): seq[string] =
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result = @[]
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var pos = 0
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while pos < str.len:
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var matches: array[2, string]
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var len = str.findBounds(tokenRE, matches, pos)
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if len.first != -1 and len.last != -1:
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pos = len.last + 1
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if matches[0][0] != ';':
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result.add matches[0]
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else:
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inc pos
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proc read_form(r: var Reader): MalType
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proc read_seq(r: var Reader, fr, to: string): seq[MalType] =
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result = @[]
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var t = r.next
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if t != fr: raise newException(ValueError, "expected '" & fr & "'")
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t = r.peek
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while t != to:
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if t == nil: raise newException(ValueError, "expected '" & to & "', got EOF")
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result.add r.read_form
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t = r.peek
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discard r.next
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proc read_list(r: var Reader): MalType =
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result = list r.read_seq("(", ")")
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proc read_vector(r: var Reader): MalType =
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result = vector r.read_seq("[", "]")
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proc read_hash_map(r: var Reader): MalType =
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result = hash_map r.read_seq("{", "}")
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proc read_atom(r: var Reader): MalType =
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let t = r.next
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if t.match(intRE): number t.parseInt
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elif t[0] == '"': str t[1 .. <t.high].replace("\\\"", "\"")
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elif t[0] == ':': keyword t[1 .. t.high]
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elif t == "nil": nilObj
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elif t == "true": trueObj
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elif t == "false": falseObj
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else: symbol t
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proc read_form(r: var Reader): MalType =
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if r.peek[0] == ';':
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discard r.next
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return nilObj
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case r.peek
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of "'":
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discard r.next
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result = list(symbol "quote", r.read_form)
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of "`":
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discard r.next
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result = list(symbol "quasiquote", r.read_form)
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of "~":
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discard r.next
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result = list(symbol "unquote", r.read_form)
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of "~@":
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discard r.next
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result = list(symbol "splice-unquote", r.read_form)
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of "^":
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discard r.next
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let meta = r.read_form
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result = list(symbol "with-meta", r.read_form, meta)
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of "@":
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discard r.next
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result = list(symbol "deref", r.read_form)
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# list
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of "(": result = r.read_list
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of ")": raise newException(ValueError, "unexpected ')'")
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# vector
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of "[": result = r.read_vector
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of "]": raise newException(ValueError, "unexpected ']'")
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# hash-map
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of "{": result = r.read_hash_map
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of "}": raise newException(ValueError, "unexpected '}'")
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# atom
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else: result = r.read_atom
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proc read_str*(str: string): MalType =
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var r = Reader(tokens: str.tokenize)
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if r.tokens.len == 0:
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raise newException(Blank, "Blank line")
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r.read_form
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