79 lines
2.3 KiB
Nim
79 lines
2.3 KiB
Nim
# SPDX-FileCopyrightText: ☭ Emery Hemingway
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# SPDX-License-Identifier: Unlicense
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## NPEG rules for Preserves.
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import npeg, npeg/lib/utf8
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when defined(nimHasUsed): {.used.}
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grammar "Preserves":
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ws <- *(' ' | '\t' | '\r' | '\n' )
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commas <- *(ws * ',') * ws
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Document <- Value * ws * !1
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Value <-
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(ws * (Record | Collection | Atom | Embedded | Compact)) |
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(ws * Annotation) |
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(ws * '#' * @'\n' * Value)
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Collection <- Sequence | Dictionary | Set
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Atom <- Boolean | Float | Double | FloatRaw | DoubleRaw | SignedInteger | String | ByteString | Symbol
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Record <- '<' * +Value * ws * '>'
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Sequence <- '[' * *(commas * Value) * commas * ']'
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Dictionary <- '{' * *(commas * Value * ws * ':' * Value) * commas * '}'
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Set <- "#{" * *(commas * Value) * commas * '}'
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Boolean <- "#f" | "#t"
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nat <- '0' | (Digit-'0') * *Digit
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int <- ?'-' * nat
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frac <- '.' * +Digit
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exp <- 'e' * ?('-'|'+') * +Digit
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flt <- int * ((frac * exp) | frac | exp)
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Float <- >flt * 'f'
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Double <- flt
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SignedInteger <- int
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char <- unescaped | '|' | (escape * (escaped | '"' | ('u' * Xdigit[4])))
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String <- '"' * >(*char) * '"'
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ByteString <- charByteString | hexByteString | b64ByteString
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charByteString <- "#\"" * >(*binchar) * '"'
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hexByteString <- "#x\"" * >(*(ws * Xdigit[2])) * ws * '"'
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base64char <- {'A'..'Z', 'a'..'z', '0'..'9', '+', '/', '-', '_', '='}
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b64ByteString <- "#[" * >(*(ws * base64char)) * ws * ']'
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binchar <- binunescaped | (escape * (escaped | '"' | ('x' * Xdigit[2])))
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binunescaped <- {' '..'!', '#'..'[', ']'..'~'}
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symchar <- (utf8.any - { 0..127, '\\', '|' }) | (escape * (escaped | ('u' * Xdigit[4]))) | "\\|"
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QuotedSymbol <- '|' * >(*symchar) * '|'
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sympunct <- {'~', '!', '$', '%', '^', '&', '*', '?', '_', '=', '+', '-', '/', '.'}
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symuchar <- utf8.any - { 0..127 }
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SymbolOrNumber <- >(+(Alpha | Digit | sympunct | symuchar))
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Symbol <- QuotedSymbol | SymbolOrNumber
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Embedded <- "#!" * Value
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Annotation <- '@' * Value * Value
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Compact <- "#=" * ws * ByteString
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unescaped <- utf8.any - { '\x00'..'\x19', '"', '\\', '|' }
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unicodeEscaped <- 'u' * Xdigit[4]
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escaped <- {'\\', '/', 'b', 'f', 'n', 'r', 't'}
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escape <- '\\'
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FloatRaw <- "#xf\"" * >((ws * Xdigit[2])[4]) * ws * '"'
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DoubleRaw <- "#xd\"" * >((ws * Xdigit[2])[8]) * ws * '"'
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