1 files changed, 132 insertions, 0 deletions
diff --git a/Master/texmf-dist/tex/lualatex/luacas/core/luacas-symbolexpression.lua b/Master/texmf-dist/tex/lualatex/luacas/core/luacas-symbolexpression.lua
new file mode 100644
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+++ b/Master/texmf-dist/tex/lualatex/luacas/core/luacas-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
+\ No newline at end of file