From 36bc0bc9b092f6dc476ce0f2be3637ff4961cbad Mon Sep 17 00:00:00 2001
From: Antonin Portelli <antonin.portelli@me.com>
Date: Thu, 30 Jan 2014 19:28:30 +0000
Subject: [PATCH] math compiler supports function calls + standard C math
 library wrapper

---
 examples/ex_test.cpp   | 13 ++++--
 latan/Function.cpp     | 81 +++++++++++++++++++++++++++++++++++
 latan/Function.hpp     | 45 ++++++++++++++++++++
 latan/Makefile.am      |  4 ++
 latan/Math.cpp         | 95 ++++++++++++++++++++++++++++++++++++++++++
 latan/Math.hpp         | 73 ++++++++++++++++++++++++++++++++
 latan/MathCompiler.cpp | 70 ++++++++++++++++++++++++++-----
 latan/MathCompiler.hpp | 45 ++++++++++++++++----
 latan/MathLexer.lpp    |  7 ++--
 latan/MathParser.ypp   | 23 ++++++++--
 latan/includes.hpp     |  1 +
 11 files changed, 426 insertions(+), 31 deletions(-)
 create mode 100644 latan/Function.cpp
 create mode 100644 latan/Function.hpp
 create mode 100644 latan/Math.cpp
 create mode 100644 latan/Math.hpp

diff --git a/examples/ex_test.cpp b/examples/ex_test.cpp
index cb03976..944dd31 100644
--- a/examples/ex_test.cpp
+++ b/examples/ex_test.cpp
@@ -1,4 +1,5 @@
 #include <iostream>
+#include <latan/Function.hpp>
 #include <latan/MathCompiler.hpp>
 
 using namespace std;
@@ -8,15 +9,21 @@ int main(int argc, char* argv[])
 {
     MathCompiler C(argv[1]);
     VarTable vtable;
+    FunctionTable ftable;
     stack<double> dstack;
     const VirtualProgram& P = C();
     
+    ftable["exp"]   = &StdMath::exp;
+    ftable["atan2"] = &StdMath::atan2;
     cout << P << endl;
-    for (int i=0;i<P.size();++i)
+    for (unsigned int i=0;i<P.size();++i)
     {
-        (*(P[i]))(dstack,vtable);
+        (*(P[i]))(dstack,vtable,ftable);
+    }
+    if (!dstack.empty())
+    {
+        cout << "result= " << dstack.top() << endl;
     }
-    cout << "result= " << dstack.top() << endl;
     
     return EXIT_SUCCESS;
 }
diff --git a/latan/Function.cpp b/latan/Function.cpp
new file mode 100644
index 0000000..9c27c2d
--- /dev/null
+++ b/latan/Function.cpp
@@ -0,0 +1,81 @@
+#include <latan/Function.hpp>
+#include <latan/includes.hpp>
+
+#define DEF_STD_FUNC_1ARG(name, funcName) \
+name##Function::name##Function(void): DoubleFunction(1) {}\
+name##Function::~name##Function(void) {}\
+double name##Function::operator()(std::vector<double> &arg)\
+{\
+    return funcName(arg[0]);\
+}\
+name##Function STDMATH_NAMESPACE::funcName;
+
+#define DEF_STD_FUNC_2ARG(name, funcName) \
+name##Function::name##Function(void): DoubleFunction(2) {}\
+name##Function::~name##Function(void) {}\
+double name##Function::operator()(std::vector<double> &arg)\
+{\
+return funcName(arg[0], arg[1]);\
+}\
+name##Function STDMATH_NAMESPACE::funcName;
+
+using namespace std;
+using namespace Latan;
+
+/******************************************************************************
+ *                            Function implementation                         *
+ ******************************************************************************/
+// constructor/destructor //////////////////////////////////////////////////////
+Function::Function(const unsigned nArg)
+: nArg_(nArg)
+{}
+
+Function::~Function(void)
+{}
+
+// access //////////////////////////////////////////////////////////////////////
+unsigned int Function::getNArg(void)
+{
+    return nArg_;
+}
+
+/******************************************************************************
+ *                        DoubleFunction implementation                       *
+ ******************************************************************************/
+DoubleFunction::DoubleFunction(const unsigned nArg)
+: Function(nArg), buffer_(nArg)
+{}
+
+DoubleFunction::~DoubleFunction(void)
+{}
+
+double DoubleFunction::operator()(std::stack<double> &arg)
+{
+    for (unsigned int i = 0; i < getNArg(); ++i)
+    {
+        buffer_[getNArg() - i - 1] = arg.top();
+        arg.pop();
+    }
+    
+    return (*this)(buffer_);
+}
+
+double DoubleFunction::operator()(const double x0, ...)
+{
+    buffer_[0] = x0;
+    if (getNArg() > 1)
+    {
+        va_list va;
+        
+        va_start(va, x0);
+        for (unsigned int i = 1; i < getNArg(); ++i)
+        {
+            buffer_[i] = va_arg(va, double);
+        }
+        va_end(va);
+    }
+    
+    return (*this)(buffer_);
+}
+
+
diff --git a/latan/Function.hpp b/latan/Function.hpp
new file mode 100644
index 0000000..de122cf
--- /dev/null
+++ b/latan/Function.hpp
@@ -0,0 +1,45 @@
+#ifndef LATAN_FUNCTION_HPP_
+#define	LATAN_FUNCTION_HPP_
+
+#include <latan/Global.hpp>
+#include <stack>
+#include <vector>
+#include <cstdarg>
+
+LATAN_BEGIN_CPPDECL
+
+/******************************************************************************
+ *                            Base function class                             *
+ ******************************************************************************/
+class Function
+{
+public:
+    // constructor/destructor
+    explicit Function(const unsigned nArg);
+    ~Function(void);
+    // access
+    unsigned int getNArg(void);
+private:
+    const unsigned int nArg_;
+};
+
+/******************************************************************************
+ *                            Double function class                           *
+ ******************************************************************************/
+class DoubleFunction: public Function
+{
+public:
+    // constructor/destructor
+    explicit DoubleFunction(const unsigned nArg);
+    virtual ~DoubleFunction(void);
+    // function call
+    virtual double operator()(std::vector<double> &arg) = 0;
+    double operator()(std::stack<double> &arg);
+    double operator()(const double x0, ...);
+private:
+    std::vector<double> buffer_;
+};
+
+LATAN_END_CPPDECL
+
+#endif
diff --git a/latan/Makefile.am b/latan/Makefile.am
index 94999bb..3fb1a75 100644
--- a/latan/Makefile.am
+++ b/latan/Makefile.am
@@ -26,12 +26,14 @@ lib_LTLIBRARIES = liblatan.la
 	
 liblatan_la_SOURCES =  \
     Exceptions.cpp     \
+    Function.cpp       \
     Global.cpp         \
     includes.hpp       \
     Io.cpp             \
     IoAsciiParser.ypp  \
     IoAsciiLexer.lpp   \
     Mat.cpp            \
+    Math.cpp           \
     MathCompiler.cpp   \
     MathParser.ypp     \
     MathLexer.lpp      \
@@ -39,10 +41,12 @@ liblatan_la_SOURCES =  \
 	../config.h
 liblatan_ladir = $(pkgincludedir)
 liblatan_la_HEADERS = \
+    Function.hpp      \
     Global.hpp        \
     Io.hpp            \
     IoObject.hpp      \
     Mat.hpp           \
+    Math.hpp          \
     MathCompiler.hpp  \
     Sample.hpp
 liblatan_la_CFLAGS = $(COM_CFLAGS)
diff --git a/latan/Math.cpp b/latan/Math.cpp
new file mode 100644
index 0000000..9b46f31
--- /dev/null
+++ b/latan/Math.cpp
@@ -0,0 +1,95 @@
+#include <latan/Math.hpp>
+#include <latan/includes.hpp>
+
+using namespace std;
+using namespace Latan;
+
+/******************************************************************************
+ *                             Standard C functions                           *
+ ******************************************************************************/
+
+#define DEF_STD_FUNC_1ARG(name, funcName) \
+name##Function::name##Function(void): DoubleFunction(1) {}\
+name##Function::~name##Function(void) {}\
+double name##Function::operator()(std::vector<double> &arg)\
+{\
+    return funcName(arg[0]);\
+}\
+name##Function STDMATH_NAMESPACE::funcName;
+
+#define DEF_STD_FUNC_2ARG(name, funcName) \
+name##Function::name##Function(void): DoubleFunction(2) {}\
+name##Function::~name##Function(void) {}\
+double name##Function::operator()(std::vector<double> &arg)\
+{\
+    return funcName(arg[0], arg[1]);\
+}\
+name##Function STDMATH_NAMESPACE::funcName;
+
+// Trigonometric functions
+DEF_STD_FUNC_1ARG(Cos,   cos)
+DEF_STD_FUNC_1ARG(Sin,   sin)
+DEF_STD_FUNC_1ARG(Tan,   tan)
+DEF_STD_FUNC_1ARG(ACos,  acos)
+DEF_STD_FUNC_1ARG(ASin,  asin)
+DEF_STD_FUNC_1ARG(ATan,  atan)
+DEF_STD_FUNC_2ARG(ATan2, atan2)
+
+// Hyperbolic functions
+DEF_STD_FUNC_1ARG(Cosh, cosh)
+DEF_STD_FUNC_1ARG(Sinh, sinh)
+DEF_STD_FUNC_1ARG(Tanh, tanh)
+
+// Exponential and logarithmic functions
+DEF_STD_FUNC_1ARG(Exp, exp)
+DEF_STD_FUNC_1ARG(Log, log)
+
+// Power functions
+DEF_STD_FUNC_2ARG(Pow,  pow)
+DEF_STD_FUNC_1ARG(Sqrt, sqrt)
+
+// Rounding and remainder functions
+DEF_STD_FUNC_1ARG(Ceil,  ceil)
+DEF_STD_FUNC_1ARG(Floor, floor)
+DEF_STD_FUNC_2ARG(FMod,  fmod)
+
+// Minimum, maximum, difference functions
+DEF_STD_FUNC_2ARG(FDim, fdim)
+DEF_STD_FUNC_2ARG(FMax, fmax)
+DEF_STD_FUNC_2ARG(FMin, fmin)
+
+// Absolute value
+DEF_STD_FUNC_1ARG(Abs, abs)
+
+#define ADD_FUNC(func) fTable[#func] = &STDMATH_NAMESPACE::func
+void STDMATH_NAMESPACE::addStdMathFunc(FunctionTable &fTable)
+{
+    // Trigonometric functions
+    ADD_FUNC(cos);
+    ADD_FUNC(sin);
+    ADD_FUNC(tan);
+    ADD_FUNC(acos);
+    ADD_FUNC(asin);
+    ADD_FUNC(atan);
+    ADD_FUNC(atan2);
+    // Hyperbolic functions
+    ADD_FUNC(cosh);
+    ADD_FUNC(sinh);
+    ADD_FUNC(tanh);
+    // Exponential and logarithmic functions
+    ADD_FUNC(exp);
+    ADD_FUNC(log);
+    // Power functions
+    ADD_FUNC(pow);
+    ADD_FUNC(sqrt);
+    // Rounding and remainder functions
+    ADD_FUNC(ceil);
+    ADD_FUNC(floor);
+    ADD_FUNC(fmod);
+    // Minimum, maximum, difference functions
+    ADD_FUNC(fdim);
+    ADD_FUNC(fmax);
+    ADD_FUNC(fmin);
+    // Absolute value
+    ADD_FUNC(abs);
+}
diff --git a/latan/Math.hpp b/latan/Math.hpp
new file mode 100644
index 0000000..8246f1b
--- /dev/null
+++ b/latan/Math.hpp
@@ -0,0 +1,73 @@
+#ifndef LATAN_MATH_HPP_
+#define	LATAN_MATH_HPP_
+
+#include <latan/Global.hpp>
+#include <latan/Function.hpp>
+#include <latan/MathCompiler.hpp>
+#include <vector>
+
+LATAN_BEGIN_CPPDECL
+
+/******************************************************************************
+ *                             Standard C functions                           *
+ ******************************************************************************/
+#define STDMATH_NAMESPACE StdMath
+
+#define DECL_STD_FUNC(name, funcName) \
+class name##Function: public DoubleFunction\
+{\
+public:\
+    name##Function(void);\
+    virtual ~name##Function(void);\
+    using DoubleFunction::operator();\
+    virtual double operator()(std::vector<double> &arg);\
+};\
+namespace STDMATH_NAMESPACE\
+{\
+    extern name##Function funcName;\
+}
+
+// Trigonometric functions
+DECL_STD_FUNC(Cos,   cos)
+DECL_STD_FUNC(Sin,   sin)
+DECL_STD_FUNC(Tan,   tan)
+DECL_STD_FUNC(ACos,  acos)
+DECL_STD_FUNC(ASin,  asin)
+DECL_STD_FUNC(ATan,  atan)
+DECL_STD_FUNC(ATan2, atan2)
+
+// Hyperbolic functions
+DECL_STD_FUNC(Cosh, cosh)
+DECL_STD_FUNC(Sinh, sinh)
+DECL_STD_FUNC(Tanh, tanh)
+
+// Exponential and logarithmic functions
+DECL_STD_FUNC(Exp, exp)
+DECL_STD_FUNC(Log, log)
+
+// Power functions
+DECL_STD_FUNC(Pow,  pow)
+DECL_STD_FUNC(Sqrt, sqrt)
+
+// Rounding and remainder functions
+DECL_STD_FUNC(Ceil,  ceil)
+DECL_STD_FUNC(Floor, floor)
+DECL_STD_FUNC(FMod,  fmod)
+
+// Minimum, maximum, difference functions
+DECL_STD_FUNC(FDim, fdim)
+DECL_STD_FUNC(FMax, fmax)
+DECL_STD_FUNC(FMin, fmin)
+
+// Absolute value
+DECL_STD_FUNC(Abs, abs)
+
+// Add standard math functions to a table for the math compiler
+namespace STDMATH_NAMESPACE
+{
+    void addStdMathFunc(FunctionTable &fTable);
+}
+
+LATAN_END_CPPDECL
+
+#endif
\ No newline at end of file
diff --git a/latan/MathCompiler.cpp b/latan/MathCompiler.cpp
index 25c8b5a..480bd27 100644
--- a/latan/MathCompiler.cpp
+++ b/latan/MathCompiler.cpp
@@ -29,7 +29,7 @@ MathNode::MathNode(const std::string &name, const unsigned int type,\
     va_start(va, nArg);
     for (unsigned int i = 0; i < nArg; ++i)
     {
-        arg_[i] = va_arg(va, MathNode*);
+        arg_[i] = va_arg(va, MathNode *);
         arg_[i]->parent_ = this;
     }
     va_end(va);
@@ -62,6 +62,16 @@ unsigned int MathNode::getNArg(void) const
     return static_cast<unsigned int>(arg_.size());
 }
 
+void MathNode::setName(const std::string &name)
+{
+    name_ = name;
+}
+
+void MathNode::pushArg(MathNode *node)
+{
+    arg_.push_back(node);
+}
+
 // operator ////////////////////////////////////////////////////////////////////
 const MathNode &MathNode::operator[](const unsigned int i) const
 {
@@ -102,7 +112,8 @@ Push::Push(const string &name)
 , name_(name)
 {}
 
-void Push::operator()(std::stack<double> &dStack, VarTable &vTable)
+void Push::operator()(std::stack<double> &dStack, VarTable &vTable,
+                      FunctionTable &fTable __dumb)
 {
     if (type_ == ArgType::Constant)
     {
@@ -138,8 +149,8 @@ Pop::Pop(const string &name)
 : name_(name)
 {}
 
-
-void Pop::operator()(std::stack<double> &dStack, VarTable &vTable)
+void Pop::operator()(std::stack<double> &dStack, VarTable &vTable,
+                     FunctionTable &fTable __dumb)
 {
     if (!name_.empty())
     {
@@ -157,8 +168,8 @@ Store::Store(const string &name)
 : name_(name)
 {}
 
-
-void Store::operator()(std::stack<double> &dStack, VarTable &vTable)
+void Store::operator()(std::stack<double> &dStack, VarTable &vTable,
+                       FunctionTable &fTable __dumb)
 {
     if (!name_.empty())
     {
@@ -171,8 +182,31 @@ void Store::print(std::ostream &out) const
     out << CODE_MOD << "store" << CODE_MOD << name_;
 }
 
+Call::Call(const string &name)
+: name_(name)
+{}
+
+void Call::operator()(std::stack<double> &dStack, VarTable &vTable __dumb,
+                       FunctionTable &fTable)
+{
+    if (keyExists(name_, fTable))
+    {
+        dStack.push((*fTable[name_])(dStack));
+    }
+    else
+    {
+        LATAN_ERROR(Range, "unknown function '" + name_ + "'");
+    }
+}
+
+void Call::print(std::ostream &out) const
+{
+    out << CODE_MOD << "call" << CODE_MOD << name_;
+}
+
 #define DEF_OP(name, nArg, exp, insName)\
-void name::operator()(stack<double> &dStack, VarTable &vTable __dumb)\
+void name::operator()(stack<double> &dStack, VarTable &vTable __dumb,\
+                      FunctionTable &fTable __dumb)\
 {\
     double x[nArg];\
     for (int i = 0; i < nArg; ++i)\
@@ -320,14 +354,21 @@ void MathCompiler::compile(const MathNode& n)
         case MathNode::Type::op:
             if (n.getName() == "=")
             {
-                compile(n[1]);
-                if (n.isRoot())
+                if (n[0].getType() == MathNode::Type::var)
                 {
-                    out_.push_back(new Pop(n[0].getName()));
+                    compile(n[1]);
+                    if (n.isRoot())
+                    {
+                        out_.push_back(new Pop(n[0].getName()));
+                    }
+                    else
+                    {
+                        out_.push_back(new Store(n[0].getName()));
+                    }
                 }
                 else
                 {
-                    out_.push_back(new Store(n[0].getName()));
+                    LATAN_ERROR(Compilation, "invalid LHS for '='");
                 }
             }
             else
@@ -352,6 +393,13 @@ void MathCompiler::compile(const MathNode& n)
                 compile(n[i]);
             }
             break;
+        case MathNode::Type::func:
+            for (unsigned int i = 0; i < n.getNArg(); ++i)
+            {
+                compile(n[i]);
+            }
+            out_.push_back(new Call(n.getName()));
+            break;
         default:
             LATAN_ERROR(Compilation,
                         "unknown node type (node '" + n.getName() + "')");
diff --git a/latan/MathCompiler.hpp b/latan/MathCompiler.hpp
index 61a8a0b..cd1e8ae 100644
--- a/latan/MathCompiler.hpp
+++ b/latan/MathCompiler.hpp
@@ -6,6 +6,7 @@
 #include <queue>
 #include <string>
 #include <stack>
+#include <latan/Function.hpp>
 #include <latan/Global.hpp>
 #include <latan/ParserState.hpp>
 
@@ -27,7 +28,8 @@ public:
             cst  = 0,
             op   = 1,
             var  = 2,
-            keyw = 3
+            keyw = 3,
+            func = 4
         };
     };
 public:
@@ -41,6 +43,8 @@ public:
     const std::string& getName(void) const;
     unsigned int       getType(void) const;
     unsigned int       getNArg(void) const;
+    void               setName(const std::string &name);
+    void               pushArg(MathNode *node);
     // operator
     const MathNode &operator[](const unsigned int i) const;
     // test
@@ -55,7 +59,8 @@ private:
 /******************************************************************************
  *                       Virtual machine code classes                         *
  ******************************************************************************/
-typedef std::map<std::string, double> VarTable;
+typedef std::map<std::string, double>           VarTable;
+typedef std::map<std::string, DoubleFunction *> FunctionTable;
 
 // Abstract base
 class Instruction
@@ -63,13 +68,14 @@ class Instruction
 public:
     virtual ~Instruction();
     // instruction execution
-    virtual void operator()(std::stack<double> &dStack, VarTable &vTable) = 0;
+    virtual void operator()(std::stack<double> &dStack, VarTable &vTable,
+                            FunctionTable &fTable) = 0;
     friend std::ostream& operator<<(std::ostream &out, const Instruction &ins);
 private:
     virtual void print(std::ostream &out) const = 0;
 };
 
-// push, pop and store
+// Push
 class Push: public Instruction
 {
 private:
@@ -87,7 +93,8 @@ public:
     explicit Push(const double val);
     explicit Push(const std::string &name);
     // instruction execution
-    virtual void operator()(std::stack<double> &dStack, VarTable &vTable);
+    virtual void operator()(std::stack<double> &dStack, VarTable &vTable,
+                            FunctionTable &fTable);
 private:
     virtual void print(std::ostream& out) const;
 private:
@@ -96,38 +103,58 @@ private:
     std::string  name_;
 };
 
+// Pop
 class Pop: public Instruction
 {
 public:
     //constructor
     explicit Pop(const std::string &name);
     // instruction execution
-    virtual void operator()(std::stack<double> &dStack, VarTable &vTable);
+    virtual void operator()(std::stack<double> &dStack, VarTable &vTable,
+                            FunctionTable &fTable);
 private:
     virtual void print(std::ostream& out) const;
 private:
     std::string name_;
 };
 
+// Store
 class Store: public Instruction
 {
 public:
     //constructor
     explicit Store(const std::string &name);
     // instruction execution
-    virtual void operator()(std::stack<double> &dStack, VarTable &vTable);
+    virtual void operator()(std::stack<double> &dStack, VarTable &vTable,
+                            FunctionTable &fTable);
 private:
     virtual void print(std::ostream& out) const;
 private:
     std::string name_;
 };
 
-// Float operations
+// Call function
+class Call: public Instruction
+{
+public:
+    //constructor
+    explicit Call(const std::string &name);
+    // instruction execution
+    virtual void operator()(std::stack<double> &dStack, VarTable &vTable,
+                            FunctionTable &fTable);
+private:
+    virtual void print(std::ostream& out) const;
+private:
+    std::string name_;
+};
+
+// Floating point operations
 #define DECL_OP(name)\
 class name: public Instruction\
 {\
 public:\
-    virtual void operator()(std::stack<double> &dStack, VarTable &vTable);\
+virtual void operator()(std::stack<double> &dStack, VarTable &vTable,\
+                        FunctionTable &fTable);\
 private:\
     virtual void print(std::ostream &out) const;\
 }
diff --git a/latan/MathLexer.lpp b/latan/MathLexer.lpp
index 4f6e53c..7bee910 100644
--- a/latan/MathLexer.lpp
+++ b/latan/MathLexer.lpp
@@ -42,9 +42,9 @@ DIGIT   [0-9]
 ALPHA   [a-zA-Z_]
 FLOAT   (({DIGIT}+(\.{DIGIT}*)?)|({DIGIT}*\.{DIGIT}+))([eE][+-]?{DIGIT}+)?
 KEYWORD return
-END     ;
+PUNC    [;,()]
 OP      [+\-*/^=]
-PAR     [()]
+PAR     []
 BLANK   [ \t]
 
 %%
@@ -55,12 +55,11 @@ BLANK   [ \t]
                           }
 {OP}                      {RET(*yytext);}
 {KEYWORD}                 {RET(*yytext);}
-{PAR}                     {RET(*yytext);}
+{PUNC}                    {RET(*yytext);}
 {ALPHA}({ALPHA}|{DIGIT})* {
                                strncpy(yylval->val_str,yytext,MAXIDLENGTH);
                                RETTOK(ID);
                           }
-{END}                     {RETTOK(END);}
 <*>\n                     {yylloc->last_column = 0;}
 <*>{BLANK}
 <*>.                      {yylval->val_char = yytext[0]; RETTOK(ERR);}
diff --git a/latan/MathParser.ypp b/latan/MathParser.ypp
index be60b0d..41f48ab 100644
--- a/latan/MathParser.ypp
+++ b/latan/MathParser.ypp
@@ -26,7 +26,6 @@
     Latan::MathNode *val_node;
 }
 
-%token            END
 %token <val_char> ERR
 %token <val_str>  FLOAT
 %token <val_str>  ID
@@ -39,6 +38,7 @@
 %nonassoc UMINUS
 
 %type <val_node> expr
+%type <val_node> funcargs
 
 %{
 	int _math_lex(YYSTYPE *lvalp, YYLTYPE *llocp, void *scanner);
@@ -60,7 +60,7 @@
 
 program:
      /* empty string */
-    | program expr END {state->data->push_back($2);}
+    | program expr ';' {state->data->push_back($2);}
     ;
 
 expr:
@@ -68,12 +68,15 @@ expr:
     {$$ = new MathNode($FLOAT, MathNode::Type::cst);}
     | ID
     {$$ = new MathNode($ID,MathNode::Type::var);}
+    | ID '=' expr
+    {
+        $$ = new MathNode("=", MathNode::Type::op, 2,              \
+                          new MathNode($ID,MathNode::Type::var), $3);
+    }
     | 'r' expr
     {$$ = new MathNode("return", MathNode::Type::keyw, 1, $2);}
     | '-' expr %prec UMINUS
     {$$ = new MathNode("-", MathNode::Type::op, 1, $2);}
-    | expr '=' expr
-    {$$ = new MathNode("=", MathNode::Type::op, 2, $1, $3);}
     | expr '+' expr
     {$$ = new MathNode("+", MathNode::Type::op, 2, $1, $3);}
     | expr '-' expr
@@ -86,4 +89,16 @@ expr:
     {$$ = new MathNode("^", MathNode::Type::op, 2, $1, $3);}
     | '(' expr ')'
     {$$ = $2;}
+    | ID '(' funcargs ')'
+    {$$ = $3; $$->setName($ID);}
     ;
+
+funcargs:
+     /* empty string */
+    {$$ = new MathNode("", MathNode::Type::func);}
+    | expr
+    {$$ = new MathNode("", MathNode::Type::func, 1, $1);}
+    | funcargs ',' expr
+    {$$ = $1; $$->pushArg($3);}
+    ;
+
diff --git a/latan/includes.hpp b/latan/includes.hpp
index fa9cdad..61c67d1 100644
--- a/latan/includes.hpp
+++ b/latan/includes.hpp
@@ -5,6 +5,7 @@
 #include <iostream>
 #include <iomanip>
 #include <sstream>
+#include <cmath>
 #include <cstdarg>
 #include "../config.h"