Got it working

browser.c

@@ -1,56 +1,83 @@
 #include <gtk/gtk.h>
 #include <webkit2/webkit2.h>
+#include <stdlib.h>
+#include <libguile.h>
+#include <libguile/strings.h>
 
 static void
 destroyWindowCb(GtkWidget *widget, GtkWidget *window);
 
-static
-gboolean closeWebViewCb(WebKitWebView *webView, GtkWidget *window);
+static gboolean
+closeWebViewCb(WebKitWebView *webView, GtkWidget *window);
 
 static void
 destroyWindowCb(GtkWidget *widget, GtkWidget *window) {
     gtk_main_quit();
 }
 
-static
-gboolean closeWebViewCb(WebKitWebView *webView,
+static gboolean
+closeWebViewCb(WebKitWebView *webView,
                GtkWidget *window) {
     gtk_widget_destroy(window);
     return TRUE;
 }
 
-int main(int argc, char *argv[]) {
-    // Initialize GTK+
-    gtk_init(&argc, &argv);
+WebKitWebView *webView;
+
+static SCM
+start_browser(void) {
+  /* Initialize GTK+ */
+  gtk_init(0, NULL);
 
-    // Create an 800x600 window that will contain the browser instance
+  /* Create an 800x600 window that will contain the browser instance */
   GtkWidget *main_window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+
   gtk_window_set_default_size(GTK_WINDOW(main_window), 800, 600);
 
-    // Create a browser instance
-    WebKitWebView *webView = WEBKIT_WEB_VIEW(webkit_web_view_new());
+  /* Create a browser instance */
+  webView = WEBKIT_WEB_VIEW(webkit_web_view_new());
 
-    // Put the browser area into the main window
+  /* Put the browser area into the main window */
   gtk_container_add(GTK_CONTAINER(main_window), GTK_WIDGET(webView));
 
-    // Set up callbacks so that if either the main window or the browser instance is
-    // closed, the program will exit
+  /* Set up callbacks so that if either the main window or the browser instance is */
+  /* closed, the program will exit */
   g_signal_connect(main_window, "destroy", G_CALLBACK(destroyWindowCb), NULL);
   g_signal_connect(webView, "close", G_CALLBACK(closeWebViewCb), main_window);
 
-    // Load a web page into the browser instance
-    webkit_web_view_load_uri(webView, "http://www.webkitgtk.org/");
+  /* Load a web page into the browser instance */
+  webkit_web_view_load_uri(webView, "http://google.com/");
 
-    // Make sure that when the browser area becomes visible, it will get mouse
-    // and keyboard events
+  /* Make sure that when the browser area becomes visible, it will get mouse */
+  /* and keyboard events */
   gtk_widget_grab_focus(GTK_WIDGET(webView));
 
-    // Make sure the main window and all its contents are visible
+  /* Make sure the main window and all its contents are visible */
   gtk_widget_show_all(main_window);
 
-    // Run the main GTK+ event loop
+  /* Run the main GTK+ event loop */
   gtk_main();
 
-    return 0;
+  return SCM_BOOL_T;
+}
+
+static SCM
+open_page(SCM mystring) {
+  char *c_string = scm_to_locale_string(mystring);
+  printf("Opening %s\n", c_string);
+  webkit_web_view_load_uri(webView, c_string);
+  return SCM_BOOL_T;
 }
 
+static void
+inner_main(void *data, int argc, char **argv) {
+  scm_c_define_gsubr("start-browser", 0, 0, 0, start_browser);
+  scm_c_define_gsubr("open-page", 1, 0, 0, open_page);
+  scm_shell(argc, argv);
+}
+
+int main(int argc, char *argv[]) {
+    /* Initialize Guile */
+    scm_boot_guile(argc, argv, inner_main, 0);
+    return 0;
+}

build.sh

@@ -1 +1,2 @@
-gcc $(pkg-config --cflags --libs gtk+-3.0 webkit2gtk-4.0) browser.c
+#! /usr/bin/bash
+gcc $(pkg-config --cflags --libs guile-2.2 gtk+-3.0 webkit2gtk-4.0) browser.c

test.scm

@@ -0,0 +1,3 @@
+(use-modules (ice-9 threads))
+
+(call-with-new-thread (lambda () (start-browser)))