85 lines
1.6 KiB
Plaintext
85 lines
1.6 KiB
Plaintext
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# parser.ry: Written by Tadayoshi Funaba 2006,2008,2009 -*- ruby -*-
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class Date::Delta::Parser
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prechigh
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nonassoc UNARY
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left '^'
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left '*' '/'
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left '+' ',' AND '-'
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preclow
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rule
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stmt : expr
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;
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expr : time
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| iso
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| expr '+' expr {result += val[2]}
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| expr ',' expr {result += val[2]}
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| expr AND expr {result += val[2]}
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| expr '-' expr {result -= val[2]}
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| expr '*' DIGITS {result *= val[2]}
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| expr '/' DIGITS {result /= val[2]}
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| expr '^' DIGITS {result **= val[2]}
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| '-' expr =UNARY {result = -val[1]}
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| '+' expr =UNARY {result = +val[1]}
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| '(' expr ')' {result = val[1]}
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;
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time : DIGITS unit {result = val[0] * val[1]}
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;
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unit : {result = 1} | UNIT
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;
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iso : DURATION
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;
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---- header ----
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---- inner ----
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def lookup(str)
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t = str.downcase
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k = UNITS4KEY[t]
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return [:UNIT, k] if k
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return [:AND, nil] if t == 'and'
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return [:UNKNOWNWORD, nil]
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end
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def parse(str)
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@q = []
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until str.empty?
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case str
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when /\A\s+/
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when /\AP(\d+y)?(\d+m)?(\d+d)?t?(\d+h)?(\d+m)?(\d+s)?(\d+w)?/i
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y, m, d, h, min, s, w =
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[$1, $2, $3, $4, $5, $6, $7].collect{|x| x.to_i}
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y *= UNITS4KEY['years']
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m *= UNITS4KEY['months']
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d *= UNITS4KEY['days']
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h *= UNITS4KEY['hours']
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min *= UNITS4KEY['minutes']
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s *= UNITS4KEY['seconds']
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w *= UNITS4KEY['weeks']
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@q.push [:DURATION, y + m + d + h + min + s + w]
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when /\A\d+/
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@q.push [:DIGITS, $&.to_i]
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when /\A[a-z]+/i
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@q.push lookup($&)
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when /\A.|\n/
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@q.push [$&, $&]
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end
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str = $'
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end
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@q.push [false, false]
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do_parse
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end
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def next_token
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@q.shift
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end
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---- footer ----
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