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Diffstat (limited to 'macros/luatex/latex/luacas/tex/core/symbolexpression.lua')
| -rw-r--r-- | macros/luatex/latex/luacas/tex/core/symbolexpression.lua | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/macros/luatex/latex/luacas/tex/core/symbolexpression.lua b/macros/luatex/latex/luacas/tex/core/symbolexpression.lua new file mode 100644 index 0000000000..0d9192c084 --- /dev/null +++ b/macros/luatex/latex/luacas/tex/core/symbolexpression.lua @@ -0,0 +1,132 @@ +--- @class SymbolExpression +--- An atomic expression corresponding to a symbol representing an arbitary value. +--- @field symbol string +--- @alias Symbol SymbolExpression +SymbolExpression = {} +__SymbolExpression = {} + +---------------------- +-- Instance methods -- +---------------------- + +--- Given the name of the symbol as a string, creates a new symbol. +--- @param symbol string +--- @return SymbolExpression +function SymbolExpression:new(symbol) + local o = {} + local __o = Copy(__ExpressionOperations) + __o.__index = SymbolExpression + __o.__tostring = function(a) + return a.symbol + end + __o.__eq = function(a, b) + return a.symbol == b.symbol + end + + if type(symbol) ~= "string" then + error("Sent parameter of wrong type: symbol must be a string") + end + + o.symbol = symbol + o = setmetatable(o, __o) + + return o +end + +--- @return boolean +function SymbolExpression:freeof(symbol) + return symbol~=self +end + +--- @return boolean +function SymbolExpression:isconstant() + return false +end + +--- @param other Expression +--- @return boolean +function SymbolExpression:order(other) + + -- Symbol Expressions come after constant expressions. + if other:isconstant() then + return false + end + + -- Lexographic order on symbols. + if other:type() == SymbolExpression then + for i = 1, math.min(#self.symbol, #other.symbol) do + if string.byte(self.symbol, i) ~= string.byte(other.symbol, i) then + return string.byte(self.symbol, i) < string.byte(other.symbol, i) + end + end + + return #self.symbol < #other.symbol + end + + if other.operation == BinaryOperation.POW then + return BinaryOperation(BinaryOperation.POW, {self, Integer.one()}):order(other) + end + + if other.operation == BinaryOperation.MUL then + return BinaryOperation(BinaryOperation.MUL, {self}):order(other) + end + + if other.operation == BinaryOperation.ADD then + return BinaryOperation(BinaryOperation.ADD, {self}):order(other) + end + + -- CASC Autosimplfication has some symbols appearing before functions, but that looks bad to me, so all symbols appear before products now. + if other:type() == FunctionExpression or other:type() == TrigExpression or other:type() == Logarithm then + return true + end + + return false +end + +--- Converts this symbol to an element of a polynomial ring. +--- @return PolynomialRing, boolean +function SymbolExpression:topolynomial() + return PolynomialRing({Integer.zero(), Integer.one()}, self.symbol), true +end + +----------------- +-- Inheritance -- +----------------- + +__SymbolExpression.__index = AtomicExpression +__SymbolExpression.__call = SymbolExpression.new +SymbolExpression = setmetatable(SymbolExpression, __SymbolExpression) + + +---------------------- +-- Static Constants -- +---------------------- + +-- The constant pi. +PI = SymbolExpression("pi") +function PI:tolatex() + return "\\pi " +end + +-- Approximates pi as a rational number. Uses continued fraction expansion. +function PI:approximate() + return Integer(313383936) / Integer(99753205) +end + +--function PI:isconstant() +-- return true +--end + +-- The constant e. +E = SymbolExpression("e") + +-- Approximates pi as a rational number. Uses continued fraction expansion. +function E:approximate() + return Integer(517656) / Integer(190435) +end + +-- The imaginary constant i. +I = SymbolExpression("i") +function I:tolatex() + return "i" +end
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