missed those files in my previous commit

MathEval/parser.y

+%{
+/*
+ * Copyright (C) 1999, 2002, 2003  Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU libmatheval
+ *
+ * GNU libmatheval is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * GNU libmatheval is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with program; see the file COPYING. If not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+ * USA.
+ */
+
+/* This file was modified for inclusion in Gmsh */
+
+#include "common.h"
+#include "node.h"
+
+/* Variables used to communicate with code using parser.  */
+extern Node* matheval_root; /* Root of tree representation of function.  */
+extern int matheval_ok; /* Flag representing success of parsing.  */
+
+/* Report parsing error.  */
+int yyerror (char *s);
+
+/* Function used to tokenize string representing function (this function
+   is generated by scanner generator).  */
+int yylex (void);
+%}
+
+/* Parser semantic values type.  */
+%union {
+  Node *node;
+  Record *record;
+}
+
+/* Grammar terminal symbols.  */
+%token <node> NUMBER VARIABLE
+%token <record> FUNCTION
+
+/* Grammar non-terminal symbols.  */
+%type <node> expression
+
+%left '-' '+'
+%left '*' '/'
+%left NEG
+%left '^'
+
+/* Grammar start non-terminal.  */
+%start input
+
+%%
+
+input
+: expression '\n' {
+  matheval_root = $1;
+  yyerrok;
+  return 1;
+}
+;
+
+expression
+: NUMBER {
+  $$ = $1;
+}
+| VARIABLE {
+  $$ = $1;
+}
+| expression '+' expression {
+  /* Create addition binary operator node.  */
+  $$ = node_create ('b', '+', $1, $3);
+}
+| expression '-' expression {
+  /* Create subtraction binary operator node.  */
+  $$ = node_create ('b', '-', $1, $3);
+}
+| expression '*' expression {
+  /* Create multiplication binary operator node.  */
+  $$ = node_create ('b', '*', $1, $3);
+}
+| expression '/' expression {
+  /* Create division binary operator node.  */
+  $$ = node_create ('b', '/', $1, $3);
+}
+| '-' expression %prec NEG {
+  /* Create minus unary operator node.  */
+  $$ = node_create ('u', '-', $2);
+}
+| expression '^' expression {
+  /* Create exponentiation unary operator node.  */
+  $$ = node_create ('b', '^', $1, $3);
+}
+| FUNCTION '(' expression ')' {
+  /* Create function node.  */
+  $$ = node_create ('f', $1, $3);
+}
+| '(' expression ')' {
+  $$ = $2;
+}
+;
+
+%%
+
+int yyerror(char* s)
+{
+  /* Indicate parsing error through appropriate flag and stop
+     parsing.  */
+  matheval_ok = 0;
+  return 0;
+}

MathEval/scanner.l

+%{
+/*
+ * Copyright (C) 1999, 2002, 2003  Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU libmatheval
+ *
+ * GNU libmatheval is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * GNU libmatheval is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with program; see the file COPYING. If not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+ * USA.
+ */
+
+/* This file was modified for inclusion in Gmsh */
+
+#include "common.h"
+#include "node.h"
+#include "parser.h"
+#include "symbol_table.h"
+
+/* Redefine macro to redirect scanner input from string instead of
+   standard input.  */
+#define YY_INPUT( buffer, result, max_size ) \
+{ result = input_from_string (buffer, max_size); }
+
+/* Variables used to communicate with code using scanner.  */
+extern SymbolTable *matheval_symbol_table; /* Evaluator symbol table.  */
+extern char *matheval_input_string; /* String representing function.  */
+
+/* Read next max_size character from string into buffer.  */
+static int input_from_string (char *buffer, int max_size);
+%}
+
+/* Token definitions.  */
+whitespace [\ \t]+
+digit [0-9]
+number ({digit}+|{digit}+"."{digit}*|{digit}*"."{digit}+)([Ee][-+]?{digit}+)?
+function "Exp"|"Log"|"Sqrt"|"Sin"|"Cos"|"Tan"|"Ctan"|"Asin"|"Acos"|"Atan"|"Actan"|"Sinh"|"Cosh"|"Tanh"|"Ctanh"|"Asinh"|"Acosh"|"Atanh"|"Actanh"|"Fabs"
+identifier [a-zA-Z\_][a-zA-Z0-9\_]*
+
+%%
+
+{whitespace}
+
+{number} {
+  /* Create node representing constant with appropriate value.  */
+  melval.node = node_create ('c', atof (metext));
+  return NUMBER;
+}
+
+{function} {
+  /* Find symbol table record corresponding to function name.  */
+  melval.record = symbol_table_lookup (matheval_symbol_table, metext);
+  return FUNCTION;
+}
+
+{identifier} {
+  Record *record; /* Symbol table record.  */
+  /* Inserty variable into symbol table.  */
+  record = symbol_table_insert (matheval_symbol_table, metext, 'v');
+  melval.node = node_create ('v', record);
+  return VARIABLE;
+}
+
+"+" {
+  return '+';
+}
+
+"-" {
+  return '-';
+}
+
+"*" {
+  return '*';
+}
+
+"/" {
+  return '/';
+}
+
+"^" {
+  return '^';
+}
+
+"(" {
+  return '(';
+}
+
+")" {
+  return ')';
+}
+
+"\n" {
+  return '\n';
+}
+
+%%
+
+#undef mewrap
+
+int mewrap() {return 1;}
+
+static int input_from_string (char *buffer, int max_size)
+{
+  int count; /* Count of characters to copy from input string to buffer.  */
+
+  /* Calculate count of characters to copy.  */
+  count = strlen (matheval_input_string);
+  if (count > max_size)
+    count = max_size;
+
+  /* Perform copy operation and update input string.  */
+  memcpy(buffer, matheval_input_string, count);
+  matheval_input_string += count;
+
+  return count;
+}

Plugin/Evaluate.cpp

+// $Id: Evaluate.cpp,v 1.1 2004-05-12 03:23:31 geuzaine Exp $
+//
+// Copyright (C) 1997-2004 C. Geuzaine, J.-F. Remacle
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+// USA.
+// 
+// Please report all bugs and problems to <gmsh@geuz.org>.
+
+#include "Plugin.h"
+#include "Evaluate.h"
+#include "List.h"
+#include "Views.h"
+#include "Context.h"
+#include "Numeric.h"
+
+#if defined(HAVE_MATH_EVAL)
+#include "matheval.h"
+#endif
+
+extern Context_T CTX;
+
+StringXNumber EvaluateOptions_Number[] = {
+  {GMSH_FULLRC, "TimeStep", NULL, 0.},
+  {GMSH_FULLRC, "iView", NULL, -1.}
+};
+
+StringXString EvaluateOptions_String[] = {
+  {GMSH_FULLRC, "Expression", NULL, "Sin(v) * Sqrt(x^2+y^2)"}
+};
+
+extern "C"
+{
+  GMSH_Plugin *GMSH_RegisterEvaluatePlugin()
+  {
+    return new GMSH_EvaluatePlugin();
+  }
+}
+
+
+GMSH_EvaluatePlugin::GMSH_EvaluatePlugin()
+{
+  ;
+}
+
+void GMSH_EvaluatePlugin::getName(char *name) const
+{
+  strcpy(name, "Evaluate");
+}
+
+void GMSH_EvaluatePlugin::getInfos(char *author, char *copyright,
+				   char *help_text) const
+{
+  strcpy(author, "C. Geuzaine (geuz@geuz.org)");
+  strcpy(copyright, "DGR (www.multiphysics.com)");
+  strcpy(help_text,
+         "Plugin(Evaluate) sets the values associated with\n"
+         "the `TimeStep'-th time step in the view `iView'\n"
+	 "to the expression `Expression'. In addition to\n"
+	 "the usual mathematical functions, `Expression' can\n"
+	 "contain the symbols x, y, z and v, which represent\n"
+	 "the three spatial coordinates and the value of the\n"
+	 "field, respectively.\n"
+	 "\n"
+	 "Plugin(Evaluate) is executed in-place.\n");
+}
+
+int GMSH_EvaluatePlugin::getNbOptions() const
+{
+  return sizeof(EvaluateOptions_Number) / sizeof(StringXNumber);
+}
+
+StringXNumber *GMSH_EvaluatePlugin::getOption(int iopt)
+{
+  return &EvaluateOptions_Number[iopt];
+}
+
+int GMSH_EvaluatePlugin::getNbOptionsStr() const
+{
+  return sizeof(EvaluateOptions_String) / sizeof(StringXString);
+}
+
+StringXString *GMSH_EvaluatePlugin::getOptionStr(int iopt)
+{
+  return &EvaluateOptions_String[iopt];
+}
+
+void GMSH_EvaluatePlugin::catchErrorMessage(char *errorMessage) const
+{
+  strcpy(errorMessage, "Evaluate failed...");
+}
+
+static void evaluateList(Post_View * v, List_T * list, int nbElm,
+			 int nbNod, int timeStep, char *expression)
+{
+#if !defined(HAVE_MATH_EVAL)
+
+  Msg(GERROR, "MathEval is not compiled in this version of Gmsh");
+
+#else
+
+  double *x, *y, *z, *val;
+  int nb, i, j;
+
+  if(!nbElm)
+    return;
+
+  v->Changed = 1;
+
+  if(timeStep < 0 || timeStep > v->NbTimeStep - 1){
+    Msg(WARNING, "Invalid TimeStep (%d) in View[%d]: choosing TimeStep 0",
+	timeStep, v->Index);
+    timeStep = 0;
+  }
+
+  void *f = evaluator_create(expression);
+
+  if(!f){
+    Msg(GERROR, "Invalid expression '%s'", expression);
+    return;
+  }
+
+  double min = VAL_INF;
+  double max = -VAL_INF;
+
+  nb = List_Nbr(list) / nbElm;
+  for(i = 0; i < List_Nbr(list); i += nb) {
+    x = (double *)List_Pointer_Fast(list, i);
+    y = (double *)List_Pointer_Fast(list, i + nbNod);
+    z = (double *)List_Pointer_Fast(list, i + 2 * nbNod);
+    val = (double *)List_Pointer_Fast(list, i + 3 * nbNod);
+    for(j = 0; j < nbNod; j++) {
+
+      double xx = x[j];
+      double yy = y[j];
+      double zz = z[j];
+      double vv = val[nbNod * timeStep + j];
+
+      char *names[] = { "x", "y" , "z", "v" };
+      double values[] = { xx , yy, zz, vv };
+      double res = evaluator_evaluate(f, sizeof(names)/sizeof(names[0]), names, values);
+
+      val[nbNod * timeStep + j] = res;
+      if(res < min) min = res;
+      if(res > max) max = res;
+    }
+  }
+
+  evaluator_destroy(f);
+  
+  v->TimeStepMin[timeStep] = min;
+  v->TimeStepMax[timeStep] = max;
+  v->Min = v->TimeStepMin[0];
+  v->Max = v->TimeStepMax[0];
+  for(int i = 1; i < v->NbTimeStep; i++){
+    if(v->TimeStepMin[i] < v->Min) v->Min = v->TimeStepMin[i];
+    if(v->TimeStepMax[i] > v->Max) v->Max = v->TimeStepMax[i];
+  }
+
+#endif
+}
+
+static void evaluate(Post_View * v, int timeStep, char *expression)
+{
+  evaluateList(v, v->SP, v->NbSP, 1, timeStep, expression);
+  evaluateList(v, v->SL, v->NbSL, 2, timeStep, expression);
+  evaluateList(v, v->ST, v->NbST, 3, timeStep, expression);
+  evaluateList(v, v->SQ, v->NbSQ, 4, timeStep, expression);
+  evaluateList(v, v->SS, v->NbSS, 4, timeStep, expression);
+  evaluateList(v, v->SH, v->NbSH, 8, timeStep, expression);
+  evaluateList(v, v->SI, v->NbSI, 6, timeStep, expression);
+  evaluateList(v, v->SY, v->NbSY, 5, timeStep, expression);
+}
+
+Post_View *GMSH_EvaluatePlugin::execute(Post_View * v)
+{
+  Post_View *vv;
+
+  int timeStep = (int)EvaluateOptions_Number[0].def;
+  int iView = (int)EvaluateOptions_Number[1].def;
+  char *expr = EvaluateOptions_String[0].def;
+
+  if(v && iView < 0)
+    vv = v;
+  else {
+    if(!v && iView < 0)
+      iView = 0;
+    if(!(vv = (Post_View *) List_Pointer_Test(CTX.post.list, iView))) {
+      Msg(WARNING, "View[%d] does not exist", iView);
+      return 0;
+    }
+  }
+
+  evaluate(vv, timeStep, expr);
+  return vv;
+}
+

Plugin/Evaluate.h

+#ifndef _EVALUATE_H_
+#define _EVALUATE_H
+
+// Copyright (C) 1997-2004 C. Geuzaine, J.-F. Remacle
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+// USA.
+// 
+// Please report all bugs and problems to <gmsh@geuz.org>.
+
+#include "Plugin.h"
+
+extern "C"
+{
+  GMSH_Plugin *GMSH_RegisterEvaluatePlugin();
+}
+
+class GMSH_EvaluatePlugin : public GMSH_Post_Plugin
+{
+public:
+  GMSH_EvaluatePlugin();
+  void getName(char *name) const;
+  void getInfos(char *author, char *copyright, char *helpText) const;
+  void catchErrorMessage(char *errorMessage) const;
+  int getNbOptions() const;
+  StringXNumber* getOption(int iopt);  
+  int getNbOptionsStr() const;
+  StringXString* getOptionStr(int iopt);  
+  Post_View *execute(Post_View *);
+};
+
+#endif