NimYAML/yaml/hints.nim

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Nim

# NimYAML - YAML implementation in Nim
# (c) Copyright 2016 Felix Krause
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
## =================
## Module yaml.hints
## =================
##
## The hints API enables you to guess the type of YAML scalars.
import macros
import ../private/internal
type
TypeHint* = enum
## A type hint can be computed from scalar content and tells you what
## NimYAML thinks the scalar's type is. It is generated by
## `guessType <#guessType,string>`_ The first matching RegEx
## in the following table will be the type hint of a scalar string.
##
## You can use it to determine the type of YAML scalars that have a '?'
## non-specific tag, but using this feature is completely optional.
##
## ================== =========================
## Name RegEx
## ================== =========================
## ``yTypeInteger`` ``0 | -? [1-9] [0-9]*``
## ``yTypeFloat`` ``-? [1-9] ( \. [0-9]* [1-9] )? ( e [-+] [1-9] [0-9]* )?``
## ``yTypeFloatInf`` ``-? \. (inf | Inf | INF)``
## ``yTypeFloatNaN`` ``-? \. (nan | NaN | NAN)``
## ``yTypeBoolTrue`` ``y|Y|yes|Yes|YES|true|True|TRUE|on|On|ON``
## ``yTypeBoolFalse`` ``n|N|no|No|NO|false|False|FALSE|off|Off|OFF``
## ``yTypeNull`` ``~ | null | Null | NULL``
## ``yTypeTimestamp`` see `here <http://yaml.org/type/timestamp.html>`_.
## ``yTypeUnknown`` ``*``
## ================== =========================
yTypeInteger, yTypeFloat, yTypeFloatInf, yTypeFloatNaN, yTypeBoolTrue,
yTypeBoolFalse, yTypeNull, yTypeUnknown, yTypeTimestamp
YamlTypeHintState = enum
ythInitial,
ythF, ythFA, ythFAL, ythFALS, ythFALSE,
ythN, ythNU, ythNUL, ythNULL,
ythNO,
ythO, ythON,
ythOF, ythOFF,
ythT, ythTR, ythTRU, ythTRUE,
ythY, ythYE, ythYES,
ythPoint, ythPointI, ythPointIN, ythPointINF,
ythPointN, ythPointNA, ythPointNAN,
ythLowerFA, ythLowerFAL, ythLowerFALS,
ythLowerNU, ythLowerNUL,
ythLowerOF,
ythLowerTR, ythLowerTRU,
ythLowerYE,
ythPointLowerIN, ythPointLowerN, ythPointLowerNA,
ythMinus, yth0, ythInt1, ythInt1Zero, ythInt2, ythInt2Zero, ythInt3,
ythInt3Zero, ythInt4, ythInt4Zero, ythInt,
ythDecimal, ythNumE, ythNumEPlusMinus, ythExponent,
ythYearMinus, ythMonth1, ythMonth2, ythMonthMinus, ythMonthMinusNoYmd,
ythDay1, ythDay1NoYmd, ythDay2, ythDay2NoYmd,
ythAfterDayT, ythAfterDaySpace, ythHour1, ythHour2, ythHourColon,
ythMinute1, ythMinute2, ythMinuteColon, ythSecond1, ythSecond2, ythFraction,
ythAfterTimeSpace, ythAfterTimeZ, ythAfterTimePlusMinus, ythTzHour1,
ythTzHour2, ythTzHourColon, ythTzMinute1, ythTzMinute2
macro typeHintStateMachine(c: untyped, content: untyped): typed =
yAssert content.kind == nnkStmtList
result = newNimNode(nnkCaseStmt, content).add(copyNimNode(c))
for branch in content.children:
yAssert branch.kind == nnkOfBranch
var
charBranch = newNimNode(nnkOfBranch, branch)
i = 0
stateBranches = newNimNode(nnkCaseStmt, branch).add(
newIdentNode("typeHintState"))
while branch[i].kind != nnkStmtList:
charBranch.add(copyNimTree(branch[i]))
inc(i)
for rule in branch[i].children:
yAssert rule.kind == nnkInfix
yAssert $rule[0].ident == "=>"
var stateBranch = newNimNode(nnkOfBranch, rule)
case rule[1].kind
of nnkBracket:
for item in rule[1].children: stateBranch.add(item)
of nnkIdent: stateBranch.add(rule[1])
else: internalError("Invalid rule kind: " & $rule[1].kind)
if rule[2].kind == nnkNilLit:
stateBranch.add(newStmtList(newNimNode(nnkDiscardStmt).add(
newEmptyNode())))
else:
stateBranch.add(newStmtList(newAssignment(
newIdentNode("typeHintState"), copyNimTree(rule[2]))))
stateBranches.add(stateBranch)
stateBranches.add(newNimNode(nnkElse).add(newStmtList(
newNimNode(nnkReturnStmt).add(newIdentNode("yTypeUnknown")))))
charBranch.add(newStmtList(stateBranches))
result.add(charBranch)
result.add(newNimNode(nnkElse).add(newStmtList(
newNimNode(nnkReturnStmt).add(newIdentNode("yTypeUnknown")))))
template advanceTypeHint(ch: char) {.dirty.} =
typeHintStateMachine ch:
of '~': ythInitial => ythNULL
of '.':
[yth0, ythInt1, ythInt2, ythInt3, ythInt4, ythInt] => ythDecimal
[ythInitial, ythMinus] => ythPoint
ythSecond2 => ythFraction
of '+':
ythNumE => ythNumEPlusMinus
[ythFraction, ythSecond2] => ythAfterTimePlusMinus
of '-':
ythInitial => ythMinus
ythNumE => ythNumEPlusMinus
[ythInt4, ythInt4Zero] => ythYearMinus
ythMonth1 => ythMonthMinusNoYmd
ythMonth2 => ythMonthMinus
[ythFraction, ythSecond2] => ythAfterTimePlusMinus
of ':':
[ythHour1, ythHour2] => ythHourColon
ythMinute2 => ythMinuteColon
[ythTzHour1, ythTzHour2] => ythTzHourColon
of '0':
ythInitial => ythInt1Zero
ythMinus => yth0
[ythNumE, ythNumEPlusMinus] => ythExponent
ythInt1 => ythInt2
ythInt1Zero => ythInt2Zero
ythInt2 => ythInt3
ythInt2Zero => ythInt3Zero
ythInt3 => ythInt4
ythInt3Zero => ythInt4Zero
ythInt4 => ythInt
ythYearMinus => ythMonth1
ythMonth1 => ythMonth2
ythMonthMinus => ythDay1
ythMonthMinusNoYmd => ythDay1NoYmd
ythDay1 => ythDay2
ythDay1NoYmd => ythDay2NoYmd
[ythAfterDaySpace, ythAfterDayT] => ythHour1
ythHour1 => ythHour2
ythHourColon => ythMinute1
ythMinute1 => ythMinute2
ythMinuteColon => ythSecond1
ythSecond1 => ythSecond2
ythAfterTimePlusMinus => ythTzHour1
ythTzHour1 => ythTzHour2
ythTzHourColon => ythTzMinute1
ythTzMinute1 => ythTzMinute2
[ythInt, ythDecimal, ythExponent, ythFraction] => nil
of '1'..'9':
ythInitial => ythInt1
ythInt1 => ythInt2
ythInt1Zero => ythInt2Zero
ythInt2 => ythInt3
ythInt2Zero => ythInt3Zero
ythInt3 => ythInt4
ythInt3Zero => ythInt4Zero
[ythInt4, ythMinus] => ythInt
[ythNumE, ythNumEPlusMinus] => ythExponent
ythYearMinus => ythMonth1
ythMonth1 => ythMonth2
ythMonthMinus => ythDay1
ythMonthMinusNoYmd => ythDay1NoYmd
ythDay1 => ythDay2
ythDay1NoYmd => ythDay2NoYmd
[ythAfterDaySpace, ythAfterDayT] => ythHour1
ythHour1 => ythHour2
ythHourColon => ythMinute1
ythMinute1 => ythMinute2
ythMinuteColon => ythSecond1
ythSecond1 => ythSecond2
ythAfterTimePlusMinus => ythTzHour1
ythTzHour1 => ythTzHour2
ythTzHourColon => ythTzMinute1
ythTzMinute1 => ythTzMinute2
[ythInt, ythDecimal, ythExponent, ythFraction] => nil
of 'a':
ythF => ythLowerFA
ythPointN => ythPointNA
ythPointLowerN => ythPointLowerNA
of 'A':
ythF => ythFA
ythPointN => ythPointNA
of 'e':
[yth0, ythInt, ythDecimal] => ythNumE
ythLowerFALS => ythFALSE
ythLowerTRU => ythTRUE
ythY => ythLowerYE
of 'E':
[yth0, ythInt, ythDecimal] => ythNumE
ythFALS => ythFALSE
ythTRU => ythTRUE
ythY => ythYE
of 'f':
ythInitial => ythF
ythO => ythLowerOF
ythLowerOF => ythOFF
ythPointLowerIN => ythPointINF
of 'F':
ythInitial => ythF
ythO => ythOF
ythOF => ythOFF
ythPointIN => ythPointINF
of 'i', 'I': ythPoint => ythPointI
of 'l':
ythLowerNU => ythLowerNUL
ythLowerNUL => ythNULL
ythLowerFA => ythLowerFAL
of 'L':
ythNU => ythNUL
ythNUL => ythNULL
ythFA => ythFAL
of 'n':
ythInitial => ythN
ythO => ythON
ythPoint => ythPointLowerN
ythPointI => ythPointLowerIN
ythPointLowerNA => ythPointNAN
of 'N':
ythInitial => ythN
ythO => ythON
ythPoint => ythPointN
ythPointI => ythPointIN
ythPointNA => ythPointNAN
of 'o', 'O':
ythInitial => ythO
ythN => ythNO
of 'r': ythT => ythLowerTR
of 'R': ythT => ythTR
of 's':
ythLowerFAL => ythLowerFALS
ythLowerYE => ythYES
of 'S':
ythFAL => ythFALS
ythYE => ythYES
of 't', 'T':
ythInitial => ythT
[ythDay1, ythDay2, ythDay1NoYmd, ythDay2NoYmd] => ythAfterDayT
of 'u':
ythN => ythLowerNU
ythLowerTR => ythLowerTRU
of 'U':
ythN => ythNU
ythTR => ythTRU
of 'y', 'Y': ythInitial => ythY
of 'Z': [ythSecond2, ythFraction, ythAfterTimeSpace] => ythAfterTimeZ
of ' ', '\t':
[ythSecond2, ythFraction] => ythAfterTimeSpace
[ythDay1, ythDay2, ythDay1NoYmd, ythDay2NoYmd] => ythAfterDaySpace
[ythAfterTimeSpace, ythAfterDaySpace] => nil
proc guessType*(scalar: string): TypeHint {.raises: [].} =
## Parse scalar string according to the RegEx table documented at
## `TypeHint <#TypeHind>`_.
var typeHintState: YamlTypeHintState = ythInitial
for c in scalar: advanceTypeHint(c)
case typeHintState
of ythNULL: result = yTypeNull
of ythTRUE, ythON, ythYES, ythY: result = yTypeBoolTrue
of ythFALSE, ythOFF, ythNO, ythN: result = yTypeBoolFalse
of ythInt1, ythInt2, ythInt3, ythInt4, ythInt, yth0: result = yTypeInteger
of ythDecimal, ythExponent: result = yTypeFloat
of ythPointINF: result = yTypeFloatInf
of ythPointNAN: result = yTypeFloatNaN
of ythDay2, ythSecond2, ythFraction, ythAfterTimeZ, ythTzHour1, ythTzHour2,
ythTzMinute1, ythTzMinute2: result = yTypeTimestamp
else: result = yTypeUnknown