remake ps

.gitignore

@@ -6,3 +6,4 @@ build/
 *.png
 *.svg
 *.ps
+*.pdf

error_buffer.h

@@ -9,12 +9,12 @@
  * @brief Chybové kódy
  */
 enum error_code {
-    ERR_NO_ERR              = 0,    ///< Žádná chyba
-    ERR_INVALID_ARGS        = 1,    ///< Neplatné argumenty programu
-    ERR_INVALID_FUNCTION    = 2,    ///< Zadaná matematická funkce je neplatná
-    ERR_INVALID_FILENAME    = 3,    ///< Zadaný název souboru není platný
-    ERR_INVALID_LIMITS      = 4,    ///< Zadané hranice jsou ve špatném formátu
-    ERR_BAD_ALLOC           = 5     ///< Při alokaci paměti nastala chyba
+    ERR_NO_ERR              = 0,    /* Žádná chyba */
+    ERR_INVALID_ARGS        = 1,    /* Neplatné argumenty programu */
+    ERR_INVALID_FUNCTION    = 2,    /* Zadaná matematická funkce je neplatná */
+    ERR_INVALID_FILENAME    = 3,    /* Zadaný název souboru není platný */
+    ERR_INVALID_LIMITS      = 4,    /* Zadané hranice jsou ve špatném formátu */
+    ERR_BAD_ALLOC           = 5     /* Při alokaci paměti nastala chyba */
 };
 
 /**

lex.c

@@ -212,19 +212,3 @@ const char *lex_token_str(enum token_type token) {
     default:                return "<unknown token>";
     }
 }
-
-#ifdef LEX_DEBUG
-
-void lex_debug_print_token(const struct token *tok) {
-    printf("%-20s ", lex_token_str(tok->type));
-
-    if (tok->type == TOK_NUMBER)
-        printf("%.2f\n", tok->val.num);
-    else if (tok->type == TOK_FUNCTION) {
-        printf("%s\n", fns_get()[tok->val.fn_idx].name);
-    }
-    else
-        printf("\n");
-}
-
-#endif /* LEX_DEBUG */

lex.h

@@ -114,8 +114,4 @@ const char *lex_get_error_text(const struct lexer *lex);
  */
 const char *lex_token_str(enum token_type token);
 
-#ifdef LEX_DEBUG
-void lex_debug_print_token(const struct token *tok);
-#endif /* LEX_DEBUG */
-
 #endif /* LEX_H */

main.c

@@ -44,7 +44,7 @@ static int parse_range(const char *str, struct graph_range *range) {
     return 1;
 }
 
-static enum error_code export_to_file(const struct expr_node *node, const struct graph_range *range, const char *out_name) {
+static enum error_code export_to_file(const struct expr_node *node, const struct graph_range *range, const char *function, const char *out_name) {
     FILE *file;
 
     if (!(file = fopen(out_name, "w"))) {
@@ -52,12 +52,27 @@ static enum error_code export_to_file(const struct expr_node *node, const struct
         return ERR_INVALID_FILENAME;
     }
     
-    ps_export_graph(file, node, range);
+    ps_generate_graph(file, node, range, function);
 
     fclose(file);
     return ERR_NO_ERR;
 }
 
+#ifdef ENABLE_GRAPHVIZ_EXPORT
+static void export_gv(const struct expr_node *node, const char *out_name) {
+    FILE *file;
+
+    if (!(file = fopen(out_name, "w"))) {
+        fprintf(stderr, "GV: Cannot open \"%s\" for writing!\n", out_name);
+        return;
+    }
+
+    node_debug_print_gv(node, file);
+
+    fclose(file);
+}
+#endif /* ENABLE_GRAPHVIZ_EXPORT */
+
 int main(int argc, char *argv[]) { 
     enum error_code err;
     struct parser parser;
@@ -72,7 +87,7 @@ int main(int argc, char *argv[]) {
     if (argc > 3) {
         if (!parse_range(argv[3], &range)) {
             fprintf(stderr, "Invalid format of ranges! The correct format is \"xMin:xMax:yMin:yMax\".\n");
-            return ERR_INVALID_ARGS;
+            return ERR_INVALID_LIMITS;
         }
     }
     else {
@@ -89,11 +104,11 @@ int main(int argc, char *argv[]) {
         return parser_get_error(&parser);
     }
     
-    err = export_to_file(node, &range, argv[2]);
+    err = export_to_file(node, &range, argv[1], argv[2]);
 
-    /* file = fopen("graph.dot", "w");
-    node_debug_print_gv(node, file);
-    fclose(file); */
+#ifdef ENABLE_GRAPHVIZ_EXPORT
+    export_gv(node, "graph.dot");
+#endif /* ENABLE_GRAPHVIZ_EXPORT */
 
     node_free(node);
 

math_functions.c

@@ -28,7 +28,7 @@ MAKE_FUNCTION_1_ARG(tanh)
 MAKE_FUNCTION_1_ARG(floor)
 MAKE_FUNCTION_1_ARG(ceil)
 
-static double mf_sgn(double *y, const double *args) {
+static enum eval_result mf_sgn(double *y, const double *args) {
     if (args[0] < 0.0)
         *y = -1.0;
     else if (args[0] > 0.0)
@@ -39,7 +39,7 @@ static double mf_sgn(double *y, const double *args) {
     return EVAL_OK;
 }
 
-static double mf_min(double *y, const double *args) {
+static enum eval_result mf_min(double *y, const double *args) {
     if (args[0] < args[1])
         *y = args[0];
     else
@@ -48,7 +48,7 @@ static double mf_min(double *y, const double *args) {
     return EVAL_OK;
 }
 
-static double mf_max(double *y, const double *args) {
+static enum eval_result mf_max(double *y, const double *args) {
     if (args[0] > args[1])
         *y = args[0];
     else
@@ -57,7 +57,7 @@ static double mf_max(double *y, const double *args) {
     return EVAL_OK;
 }
 
-static double mf_mod(double *y, const double *args) {
+static enum eval_result mf_mod(double *y, const double *args) {
     errno = 0;
     *y = fmod(args[0], args[1]);
 

parser.c

@@ -1,5 +1,6 @@
 #include <stdlib.h>
 #include <stdio.h>
+#include <stdarg.h>
 #include "parser.h"
 
 /* Vrátí ukazatel na aktuální token */
@@ -42,8 +43,9 @@ static void error_bad_alloc(struct parser *parser) {
     error_printf(&parser->eb, "Out of memory\n");
 }
 
-static void error_expected_one_of(struct parser *parser, const int expected[]) {
+static void error_expected_tokens(struct parser *parser, size_t num_tokens, ...) {
     size_t i;
+    va_list ap;
 
     enum token_type got = get_token(parser)->type;
 
@@ -56,24 +58,22 @@ static void error_expected_one_of(struct parser *parser, const int expected[]) {
     error_set(&parser->eb, ERR_INVALID_FUNCTION);
     error_printf(&parser->eb, "Syntax error - expected ");
 
-    for (i = 0; expected[i] >= 0; ++i) {
+    va_start(ap, num_tokens);
+    for (i = 0; i < num_tokens; ++i) {
+        enum token_type tok = va_arg(ap, enum token_type);
+
         if (i > 0)
             error_printf(&parser->eb, ", ");
 
-        error_printf(&parser->eb, "%s", lex_token_str(expected[i]));
+        error_printf(&parser->eb, "%s", lex_token_str(tok));
     }
+    va_end(ap);
 
     error_printf(&parser->eb, " - but got %s\n", lex_token_str(got));
 
     lex_print_position(&parser->lexer, &parser->eb);
 }
 
-static void error_expected_single(struct parser *parser, enum token_type expected) {
-    static int expected_arr[] = { -1, -1 };
-    expected_arr[0] = expected;
-    error_expected_one_of(parser, expected_arr);
-}
-
 static struct expr_node* parse_subexpression(struct parser *parser);
 int parse_n_expressions(struct parser *parser, struct expr_node **out_nodes, size_t n);
 
@@ -81,7 +81,7 @@ static struct expr_node* parse_bracketed(struct parser *parser) {
     struct expr_node* node;
 
     if (!accept_token(parser, TOK_LEFT_PAREN)) {
-        error_expected_single(parser, TOK_LEFT_PAREN);
+        error_expected_tokens(parser, 1, TOK_LEFT_PAREN);
         return NULL;
     }
 
@@ -89,7 +89,7 @@ static struct expr_node* parse_bracketed(struct parser *parser) {
         return NULL;
 
     if (!accept_token(parser, TOK_RIGHT_PAREN)) {
-        error_expected_single(parser, TOK_RIGHT_PAREN);
+        error_expected_tokens(parser, 1, TOK_RIGHT_PAREN);
         node_free(node);
         return NULL;
     }
@@ -128,7 +128,7 @@ static struct expr_node *parse_base(struct parser *parser) {
         next_token(parser);
 
         if (!accept_token(parser, TOK_LEFT_PAREN)) {
-            error_expected_single(parser, TOK_LEFT_PAREN);
+            error_expected_tokens(parser, 1, TOK_LEFT_PAREN);
             return NULL;
         }
 
@@ -145,7 +145,7 @@ static struct expr_node *parse_base(struct parser *parser) {
         }
 
         if (!accept_token(parser, TOK_RIGHT_PAREN)) {
-            error_expected_single(parser, TOK_RIGHT_PAREN);
+            error_expected_tokens(parser, 1, TOK_RIGHT_PAREN);
             node_free(node);
             return NULL;
         }
@@ -157,11 +157,7 @@ static struct expr_node *parse_base(struct parser *parser) {
         return parse_bracketed(parser);
     }
 
-    {
-        static const int expected[] = { TOK_NUMBER, TOK_VARIABLE, TOK_FUNCTION, TOK_LEFT_PAREN, -1 };
-        error_expected_one_of(parser, expected);
-    }
-
+    error_expected_tokens(parser, 4, TOK_NUMBER, TOK_VARIABLE, TOK_FUNCTION, TOK_LEFT_PAREN);
     return NULL;
 }
 
@@ -317,7 +313,7 @@ int parser_parse_n(struct parser *parser, const char *str, const char *variable_
 
     if (!token_is(parser, TOK_EOF)) {
         size_t i;
-        error_expected_single(parser, TOK_EOF);
+        error_expected_tokens(parser, 1, TOK_EOF);
         
         for (i = 0; i < n; ++i) {
             node_free(out_nodes[i]);

ps_graph.c

@@ -1,18 +1,77 @@
 #include "ps_graph.h"
 #include <math.h>
 
+#define TEMP_BUF_SIZE  128
+
+/* rozměry grafu */
 #define GRAPH_SIZE 400
 #define HALF_GRAPH_SIZE (GRAPH_SIZE / 2)
+
+#define GRAPH_CENTER_X 306
+#define GRAPH_CENTER_Y 500
+
+/* písmo */
+#define FONT "Helvetica"
+#define FONT_SIZE_HEADER    15
+#define FONT_SIZE_LABEL     12
+#define FONT_SIZE_VALUE     9
+
 #define GRID_STEP (GRAPH_SIZE / 10)
+
+/* posuny popisků */
+#define HEADER_OFFSET_Y (10)
+
+#define X_VAL_OFFSET_X (0)
+#define X_VAL_OFFSET_Y (-13)
+
+#define Y_VAL_OFFSET_X (-5)
+#define Y_VAL_OFFSET_Y (-3)
+
+#define X_LABEL_OFFSET_X (0)
+#define X_LABEL_OFFSET_Y (-30)
+
+#define Y_LABEL_OFFSET_X (-40)
+#define Y_LABEL_OFFSET_Y (-3)
+
+/* počet částí grafu funkce */
 #define FUNCTION_SEGMENTS 1000
 
-void ps_export_graph(FILE *file, const struct expr_node *node, const struct graph_range *range) {
-    int i;
-    double x;
-    int first = 1;
+/* koeficienty pro zarovnání textu */
+#define ALIGN_CENTER    (-0.5)
+#define ALIGN_RIGHT     (-1.0)
 
+static void generate_text_align(FILE *file, int x, int y, double alignment, const char *str) {
+    fprintf(file,
+        "newpath\n"
+        /* posun na cílovou pozici */
+        "%d %d moveto\n"
+        /* vložení dvou řetězců s popiskem */
+        "(%s) dup\n"
+        /* zjištění šířky a výšky řetežce, odstranění výšky ze zásobníku (nezajímá) */
+        "stringwidth pop\n"
+        /* koeficient pro zarovnání */
+        "%f mul\n"
+        /* posun o šířku doleva */
+        "0 rmoveto\n"
+        /* zobrazení řetězce */
+        "show\n"
+        "\n",
+        x, y, str, alignment
+    );
+}
+
+static void set_font(FILE *file, const char *font, int size) {
+    fprintf(file,
+        "/%s findfont\n"
+        "%d scalefont\n"
+        "setfont\n",
+        font, size
+    );
+}
+
+static void generate_grid(FILE *file, const struct graph_range *range) {
+    int i;
     fprintf(file,
-        "306 500 translate\n"
         "2 setlinewidth\n"
         "/gridline {\n"
         "   .5 setlinewidth\n"
@@ -26,62 +85,38 @@ void ps_export_graph(FILE *file, const struct expr_node *node, const struct grap
         "\n"
     );
 
-    /* mrizka */
     for (i = -HALF_GRAPH_SIZE + GRID_STEP; i < HALF_GRAPH_SIZE; i += GRID_STEP) {
         fprintf(file, "%5d     0 %5d %5d gridline\n", GRAPH_SIZE, -HALF_GRAPH_SIZE, i);
         fprintf(file, "    0 %5d %5d %5d gridline\n", GRAPH_SIZE, i, -HALF_GRAPH_SIZE);
     }
 
-    /* popisky */
-    fprintf(file,
-        "/Arial findfont\n"
-        "12 scalefont\n"
-        "setfont\n"
-    );
+    set_font(file, FONT, FONT_SIZE_VALUE);
 
+    /* hodnoty */
     for (i = -HALF_GRAPH_SIZE; i <= HALF_GRAPH_SIZE; i += GRID_STEP) {
         double inorm = (double)i / (double)GRAPH_SIZE + 0.5;
         double xval = range->xmax * inorm + range->xmin * (1.0 - inorm); 
         double yval = range->ymax * inorm + range->ymin * (1.0 - inorm); 
+        char buf[TEMP_BUF_SIZE];
 
-        fprintf(file,
-            "newpath\n"
-            "%d %d moveto\n"
-            "(%.2f) dup\n"
-            "stringwidth pop neg\n"
-            "0 rmoveto\n"
-            "-10 -3 rmoveto\n"
-            "show\n"
-            "\n",
-            -HALF_GRAPH_SIZE, i, yval
-        );
+        /* hodnota osy y */
+        snprintf(buf, TEMP_BUF_SIZE, "%.2f", yval);
+        generate_text_align(file, -HALF_GRAPH_SIZE + Y_VAL_OFFSET_X, i + Y_VAL_OFFSET_Y, ALIGN_RIGHT, buf);
 
-        fprintf(file,
-            "newpath\n"
-            "%d %d moveto\n"
-            "(%.2f) dup\n"
-            "stringwidth pop\n"
-            "2 div neg\n"
-            "-20 rmoveto\n"
-            "show\n"
-            "\n",
-            i, -HALF_GRAPH_SIZE, xval
-        );
+        /* hodnota osy x */
+        snprintf(buf, TEMP_BUF_SIZE, "%.2f", xval);
+        generate_text_align(file, i + X_VAL_OFFSET_X, -HALF_GRAPH_SIZE + X_VAL_OFFSET_Y, ALIGN_CENTER, buf);
 
     }
 
-    fprintf(file,
-        "[] 0 setdash\n"
-        "newpath\n"
-        "%d %d moveto\n"
-        "%d 0 rlineto\n"
-        "0 %d rlineto\n"
-        "%d 0 rlineto\n"
-        "closepath\n"
-        "gsave\n"
-        "clip\n",
-        -HALF_GRAPH_SIZE, -HALF_GRAPH_SIZE, GRAPH_SIZE, GRAPH_SIZE, -GRAPH_SIZE 
-    );
+    set_font(file, FONT, FONT_SIZE_LABEL);
+    generate_text_align(file, -HALF_GRAPH_SIZE + Y_LABEL_OFFSET_X, Y_LABEL_OFFSET_Y, ALIGN_RIGHT, "y");
+    generate_text_align(file, X_LABEL_OFFSET_X, -HALF_GRAPH_SIZE + X_LABEL_OFFSET_Y, ALIGN_CENTER, "x");
+}
+
+static void generate_function(FILE *file, const struct expr_node *node, const struct graph_range *range) {
+    int i;
+    int first = 1;
 
     fprintf(file,
         "2 setlinewidth\n"
@@ -92,7 +127,7 @@ void ps_export_graph(FILE *file, const struct expr_node *node, const struct grap
     for (i = 0; i < FUNCTION_SEGMENTS; ++i) {
         const char *cmd = "lineto";
         double xpos, ypos;
-        double y;
+        double x, y;
        
         x = range->xmin + (range->xmax - range->xmin) * (double)i / (double)FUNCTION_SEGMENTS;
 
@@ -115,6 +150,35 @@ void ps_export_graph(FILE *file, const struct expr_node *node, const struct grap
     fprintf(file,
         "stroke\n"
     );
+}
+
+void ps_generate_graph(FILE *file, const struct expr_node *node, const struct graph_range *range, const char *function) {
+    char buf[TEMP_BUF_SIZE];
+    
+    fprintf(file, "%d %d translate\n", GRAPH_CENTER_X, GRAPH_CENTER_Y);
+
+    if (function) {
+        set_font(file, FONT, FONT_SIZE_HEADER);
+        snprintf(buf, TEMP_BUF_SIZE, "y = %s", function);
+        generate_text_align(file, 0, HALF_GRAPH_SIZE + HEADER_OFFSET_Y, ALIGN_CENTER, buf);
+    }
+
+    generate_grid(file, range);
+
+    fprintf(file,
+        "[] 0 setdash\n"
+        "newpath\n"
+        "%d %d moveto\n"
+        "%d 0 rlineto\n"
+        "0 %d rlineto\n"
+        "%d 0 rlineto\n"
+        "closepath\n"
+        "gsave\n"
+        "clip\n",
+        -HALF_GRAPH_SIZE, -HALF_GRAPH_SIZE, GRAPH_SIZE, GRAPH_SIZE, -GRAPH_SIZE 
+    );
+
+    generate_function(file, node, range);
 
     fprintf(file,
         "grestore\n"
@@ -122,6 +186,4 @@ void ps_export_graph(FILE *file, const struct expr_node *node, const struct grap
         "0 0 0 setrgbcolor\n"
         "stroke\n"
     );
-
-
 }

ps_graph.h

@@ -9,6 +9,6 @@ struct graph_range {
 	double ymin, ymax;
 };
 
-extern void ps_export_graph(FILE *file, const struct expr_node *node, const struct graph_range *range);
+extern void ps_generate_graph(FILE *file, const struct expr_node *node, const struct graph_range *range, const char *function);
 
 #endif

tree.c

@@ -75,187 +75,6 @@ struct expr_node *node_create_fn(size_t fn_idx, struct expr_node **args) {
     return node;
 }
 
-void node_free(struct expr_node *node) {
-    if (!node) return;
-
-    switch (node->type) {
-        case EXPR_ADD:
-        case EXPR_SUB:
-        case EXPR_MULT:
-        case EXPR_DIV:
-        case EXPR_POW:
-            node_free(node->vals.binop.left);
-            node_free(node->vals.binop.right);
-            break;
-
-        case EXPR_NEG:
-            node_free(node->vals.unop);
-            break;
-
-        case EXPR_FN:
-            {
-                size_t i, num_args = fns_get()[node->vals.fn.fn_idx].num_args;
-                for (i = 0; i < num_args; ++i) {
-                    node_free(node->vals.fn.args[i]);
-                }
-            }
-            break;
-
-        default:
-            break;
-    }
-
-    free(node);
-}
-
-static void debug_indent(int indent) {
-    int i;
-    for (i = 0; i < indent; ++i)
-        printf("   ");
-}
-
-static void debug_print(struct expr_node *node, int indent);
-
-static void debug_print_binop(struct expr_node *node, const char* name, int indent) {
-    debug_indent(indent); printf("[%s]\n", name);
-    debug_print(node->vals.binop.left, indent + 1);
-    debug_print(node->vals.binop.right, indent + 1);
-}
-
-static void debug_print(struct expr_node *node, int indent) {
-
-    switch (node->type) {
-        case EXPR_ADD:
-            debug_print_binop(node, "ADD", indent);
-            break;
-
-        case EXPR_SUB:
-            debug_print_binop(node, "SUB", indent);
-            break;
-
-        case EXPR_MULT:
-            debug_print_binop(node, "MULT", indent);
-            break;
-
-        case EXPR_DIV:
-            debug_print_binop(node, "DIV", indent);
-            break;
-
-        case EXPR_POW:
-            debug_print_binop(node, "POW", indent);
-            break;
-
-        case EXPR_NEG:
-            debug_indent(indent); printf("[NEG]\n");
-            debug_print(node->vals.unop, indent + 1);
-            break;
-
-        case EXPR_CONST:
-            debug_indent(indent); printf("[CONST] %.2f\n", node->vals.num);
-            break;
-
-        case EXPR_X:
-            debug_indent(indent); printf("[X]\n");
-
-            break;
-
-        case EXPR_FN: 
-        {
-            size_t i;
-            const struct math_function *fn = &fns_get()[node->vals.fn.fn_idx];
-            debug_indent(indent); printf("[FN] %s\n", fn->name);
-
-            for (i = 0; i < fn->num_args; ++i) {
-                debug_print(node->vals.fn.args[i], indent + 1);
-            }
-
-            break;
-        }
-
-        default:
-            break;
-    }
-}
-
-
-void node_debug_print(struct expr_node *node) {
-    debug_print(node, 0);
-}
-
-static void debug_print_gv(const struct expr_node *node, FILE *output);
-
-static void debug_print_binop_gv(const struct expr_node *node, FILE *output, const char *name) {
-    fprintf(output, "node%p [label=\"%s\"]\n", (void*)node, name);
-    debug_print_gv(node->vals.binop.left, output);
-    debug_print_gv(node->vals.binop.right, output);
-    fprintf(output, "node%p -> node%p [label=left]\n", (void*)node, (void*)node->vals.binop.left);
-    fprintf(output, "node%p -> node%p [label=right]\n", (void*)node, (void*)node->vals.binop.right);
-}
-
-static void debug_print_gv(const struct expr_node *node, FILE *output) {
-
-    switch (node->type) {
-        case EXPR_ADD:
-            debug_print_binop_gv(node, output, "ADD");
-            break;
-
-        case EXPR_SUB:
-            debug_print_binop_gv(node, output, "SUB");
-            break;
-
-        case EXPR_MULT:
-            debug_print_binop_gv(node, output, "MULT");
-            break;
-
-        case EXPR_DIV:
-            debug_print_binop_gv(node, output, "DIV");
-            break;
-
-        case EXPR_POW:
-            debug_print_binop_gv(node, output, "POW");
-            break;
-
-        case EXPR_NEG:
-            fprintf(output, "node%p [label=\"NEG\"]\n", (void*)node);
-            debug_print_gv(node->vals.unop, output);
-            fprintf(output, "node%p -> node%p [label=unop]\n", (void*)node, (void*)node->vals.unop);
-            break;
-
-        case EXPR_CONST:
-            fprintf(output, "node%p [label=\"CONST: %.2f\"]\n", (void*)node, node->vals.num);
-            break;
-
-        case EXPR_X:
-            fprintf(output, "node%p [label=\"X\"]\n", (void*)node);
-            break;
-
-        case EXPR_FN:
-        {
-            size_t i;
-            const struct math_function *fn = &fns_get()[node->vals.fn.fn_idx];
-
-            fprintf(output, "node%p [label=\"FN: %s\"]\n", (void*)node, fn->name);
-
-            for (i = 0; i < fn->num_args; ++i) {
-                struct expr_node *arg = node->vals.fn.args[i];
-                debug_print_gv(arg, output);
-                fprintf(output, "node%p -> node%p [label=arg%d]\n", (void*)node, (void*)arg, (int)i + 1);
-            }
-
-            break;
-        }
-
-        default:
-            break;
-    }
-}
-
-void node_debug_print_gv(const struct expr_node *node, FILE *output) {
-    fprintf(output, "digraph G {\n");
-    debug_print_gv(node, output);
-    fprintf(output, "}\n");
-}
-
 #define INF (1.0e256)
 
 static int is_real(double x) {
@@ -346,3 +165,114 @@ enum eval_result node_eval(const struct expr_node *node, double x, double *y) {
 
     return 0.0;
 }
+
+#ifdef ENABLE_GRAPHVIZ_EXPORT
+
+static void debug_print_gv(const struct expr_node *node, FILE *output);
+
+static void debug_print_binop_gv(const struct expr_node *node, FILE *output, const char *name) {
+    fprintf(output, "node%p [label=\"%s\"]\n", (void*)node, name);
+    debug_print_gv(node->vals.binop.left, output);
+    debug_print_gv(node->vals.binop.right, output);
+    fprintf(output, "node%p -> node%p [label=left]\n", (void*)node, (void*)node->vals.binop.left);
+    fprintf(output, "node%p -> node%p [label=right]\n", (void*)node, (void*)node->vals.binop.right);
+}
+
+static void debug_print_gv(const struct expr_node *node, FILE *output) {
+
+    switch (node->type) {
+        case EXPR_ADD:
+            debug_print_binop_gv(node, output, "ADD");
+            break;
+
+        case EXPR_SUB:
+            debug_print_binop_gv(node, output, "SUB");
+            break;
+
+        case EXPR_MULT:
+            debug_print_binop_gv(node, output, "MULT");
+            break;
+
+        case EXPR_DIV:
+            debug_print_binop_gv(node, output, "DIV");
+            break;
+
+        case EXPR_POW:
+            debug_print_binop_gv(node, output, "POW");
+            break;
+
+        case EXPR_NEG:
+            fprintf(output, "node%p [label=\"NEG\"]\n", (void*)node);
+            debug_print_gv(node->vals.unop, output);
+            fprintf(output, "node%p -> node%p [label=unop]\n", (void*)node, (void*)node->vals.unop);
+            break;
+
+        case EXPR_CONST:
+            fprintf(output, "node%p [label=\"CONST: %.2f\"]\n", (void*)node, node->vals.num);
+            break;
+
+        case EXPR_X:
+            fprintf(output, "node%p [label=\"X\"]\n", (void*)node);
+            break;
+
+        case EXPR_FN:
+        {
+            size_t i;
+            const struct math_function *fn = &fns_get()[node->vals.fn.fn_idx];
+
+            fprintf(output, "node%p [label=\"FN: %s\"]\n", (void*)node, fn->name);
+
+            for (i = 0; i < fn->num_args; ++i) {
+                struct expr_node *arg = node->vals.fn.args[i];
+                debug_print_gv(arg, output);
+                fprintf(output, "node%p -> node%p [label=arg%d]\n", (void*)node, (void*)arg, (int)i + 1);
+            }
+
+            break;
+        }
+
+        default:
+            break;
+    }
+}
+
+void node_debug_print_gv(const struct expr_node *node, FILE *output) {
+    fprintf(output, "digraph G {\n");
+    debug_print_gv(node, output);
+    fprintf(output, "}\n");
+}
+
+#endif /* ENABLE_GRAPHVIZ_EXPORT */
+
+void node_free(struct expr_node *node) {
+    if (!node) return;
+
+    switch (node->type) {
+        case EXPR_ADD:
+        case EXPR_SUB:
+        case EXPR_MULT:
+        case EXPR_DIV:
+        case EXPR_POW:
+            node_free(node->vals.binop.left);
+            node_free(node->vals.binop.right);
+            break;
+
+        case EXPR_NEG:
+            node_free(node->vals.unop);
+            break;
+
+        case EXPR_FN:
+            {
+                size_t i, num_args = fns_get()[node->vals.fn.fn_idx].num_args;
+                for (i = 0; i < num_args; ++i) {
+                    node_free(node->vals.fn.args[i]);
+                }
+            }
+            break;
+
+        default:
+            break;
+    }
+
+    free(node);
+}

tree.h

@@ -115,9 +115,6 @@ struct expr_node *node_create_x(void);
  */
 struct expr_node *node_create_fn(size_t fn_idx, struct expr_node **args);
 
-void node_debug_print(struct expr_node *node);
-void node_debug_print_gv(const struct expr_node *node, FILE *output);
-
 /**
  * @brief Vyhodnotí uzel
  * 
@@ -128,6 +125,10 @@ void node_debug_print_gv(const struct expr_node *node, FILE *output);
  */
 enum eval_result node_eval(const struct expr_node *node, double x, double *y);
 
+#ifdef ENABLE_GRAPHVIZ_EXPORT
+void node_debug_print_gv(const struct expr_node *node, FILE *output);
+#endif /* ENABLE_GRAPHVIZ_EXPORT */
+
 /**
  * @brief Uvolní uzel
  *