diff --git a/Makefile b/Makefile
index 419dc561..3baea500 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,9 @@ TOPDIR=$(shell pwd)
 include $(TOPDIR)/common.mk
 
 # Depend on the object files of all source-files in src/*.c and on all header files
-FILES=$(patsubst %.c,%.o,$(wildcard src/*.c))
+AUTOGENERATED:=src/cfgparse.tab.c src/cfgparse.yy.c
+FILES:=$(filter-out $(AUTOGENERATED),$(wildcard src/*.c))
+FILES:=$(FILES:.c=.o)
 HEADERS=$(wildcard include/*.h)
 
 # Depend on the specific file (.c for each .o) and on all headers
@@ -11,13 +13,23 @@ src/%.o: src/%.c ${HEADERS}
 	echo "CC $<"
 	$(CC) $(CFLAGS) -c -o $@ $<
 
-all: ${FILES}
+all: src/cfgparse.y.o src/cfgparse.yy.o ${FILES}
 	echo "LINK i3"
-	$(CC) -o i3 ${FILES} $(LDFLAGS)
+	$(CC) -o i3 ${FILES} src/cfgparse.y.o src/cfgparse.yy.o $(LDFLAGS)
 	echo ""
 	echo "SUBDIR i3-msg"
 	$(MAKE) TOPDIR=$(TOPDIR) -C i3-msg
 
+src/cfgparse.yy.o: src/cfgparse.l
+	echo "LEX $<"
+	lex -i -o $(@:.o=.c) $<
+	$(CC) $(CFLAGS) -c -o $@ $(@:.o=.c)
+
+src/cfgparse.y.o: src/cfgparse.y
+	echo "YACC $<"
+	yacc --debug --verbose -b $(basename $< .y) -d $<
+	$(CC) $(CFLAGS) -c -o $@ $(<:.y=.tab.c)
+
 install: all
 	echo "INSTALL"
 	$(INSTALL) -d -m 0755 $(DESTDIR)/usr/bin
@@ -46,7 +58,7 @@ dist: distclean
 	rm -rf i3-${VERSION}
 
 clean:
-	rm -f src/*.o
+	rm -f src/*.o src/cfgparse.tab.{c,h} src/cfgparse.yy.c
 	$(MAKE) -C docs clean
 	$(MAKE) -C man clean
 	$(MAKE) TOPDIR=$(TOPDIR) -C i3-msg clean
diff --git a/include/config.h b/include/config.h
index 100faa4c..c0105cee 100644
--- a/include/config.h
+++ b/include/config.h
@@ -20,6 +20,7 @@
 
 typedef struct Config Config;
 extern Config config;
+extern bool config_use_lexer;
 
 /**
  * Part of the struct Config. It makes sense to group colors for background,
@@ -40,6 +41,7 @@ struct Colortriple {
 struct Variable {
         char *key;
         char *value;
+        char *next_match;
 
         SLIST_ENTRY(Variable) variables;
 };
diff --git a/src/cfgparse.l b/src/cfgparse.l
new file mode 100644
index 00000000..2332055a
--- /dev/null
+++ b/src/cfgparse.l
@@ -0,0 +1,69 @@
+%{
+#include <stdio.h>
+#include "cfgparse.tab.h"
+#include <xcb/xcb.h>
+
+#include "data.h"
+#include "config.h"
+%}
+
+%Start BIND_COND
+%Start BIND_AWS_COND
+%Start BIND_A2WS_COND
+%Start ASSIGN_COND
+%Start COLOR_COND
+%Start SCREEN_COND
+%Start SCREEN_AWS_COND
+
+%%
+<BIND_A2WS_COND>[^\n]+          { BEGIN(INITIAL); yylval.string = strdup(yytext); return STR; }
+^#[^\n]*                        { return TOKCOMMENT; }
+[0-9]+                          { yylval.number = atoi(yytext); return NUMBER; }
+<COLOR_COND>[0-9a-fA-F]+        { yylval.string = strdup(yytext); return HEX; }
+bind                            { BEGIN(BIND_COND); return TOKBIND; }
+bindsym                         { BEGIN(BIND_COND); return TOKBINDSYM; }
+floating_modifier               { return TOKFLOATING_MODIFIER; }
+workspace                       { BEGIN(INITIAL); return TOKWORKSPACE; }
+screen                          { BEGIN(SCREEN_COND); return TOKSCREEN; }
+terminal                        { BEGIN(BIND_AWS_COND); return TOKTERMINAL; }
+font                            { BEGIN(BIND_AWS_COND); return TOKFONT; }
+assign                          { BEGIN(ASSIGN_COND); return TOKASSIGN; }
+set[^\n]*                       { return TOKCOMMENT; }
+ipc-socket                      { BEGIN(BIND_AWS_COND); return TOKIPCSOCKET; }
+exec                            { BEGIN(BIND_AWS_COND); return TOKEXEC; }
+client.focused                  { BEGIN(COLOR_COND); yylval.color = &config.client.focused; return TOKCOLOR; }
+client.focused_inactive         { BEGIN(COLOR_COND); yylval.color = &config.client.focused_inactive; return TOKCOLOR; }
+client.unfocused                { BEGIN(COLOR_COND); yylval.color = &config.client.unfocused; return TOKCOLOR; }
+client.urgent                   { BEGIN(COLOR_COND); yylval.color = &config.client.urgent; return TOKCOLOR; }
+bar.focused                     { BEGIN(COLOR_COND); yylval.color = &config.client.focused; return TOKCOLOR; }
+bar.unfocused                   { BEGIN(COLOR_COND); yylval.color = &config.client.unfocused; return TOKCOLOR; }
+bar.urgent                      { BEGIN(COLOR_COND); yylval.color = &config.client.urgent; return TOKCOLOR; }
+Mod1                            { yylval.number = BIND_MOD1; return MODIFIER; }
+Mod2                            { yylval.number = BIND_MOD2; return MODIFIER; }
+Mod3                            { yylval.number = BIND_MOD3; return MODIFIER; }
+Mod4                            { yylval.number = BIND_MOD4; return MODIFIER; }
+Mod5                            { yylval.number = BIND_MOD5; return MODIFIER; }
+Mode_switch                     { yylval.number = BIND_MODE_SWITCH; return MODIFIER; }
+control                         { return TOKCONTROL; }
+shift                           { return TOKSHIFT; }
+→                               { return TOKARROW; }
+\n                              /* ignore end of line */;
+<SCREEN_AWS_COND>x              { return (int)yytext[0]; }
+<BIND_COND>[ \t]+               { BEGIN(BIND_AWS_COND); return WHITESPACE; }
+<BIND_AWS_COND>[ \t]+           { BEGIN(BIND_A2WS_COND); return WHITESPACE; }
+<SCREEN_COND>[ \t]+             { BEGIN(SCREEN_AWS_COND); return WHITESPACE; }
+<SCREEN_AWS_COND>[ \t]+         { BEGIN(BIND_A2WS_COND); return WHITESPACE; }
+[ \t]+                          { return WHITESPACE; }
+\"[^\"]+\"                      {
+                                  /* if ASSIGN_COND then */
+                                  BEGIN(INITIAL);
+                                  /* yylval will be the string, but without quotes */
+                                  char *copy = strdup(yytext+1);
+                                  copy[strlen(copy)-1] = '\0';
+                                  yylval.string = copy;
+                                  return QUOTEDSTRING;
+                                }
+<ASSIGN_COND>[^ \t]+            { BEGIN(INITIAL); yylval.string = strdup(yytext); return STR_NG; }
+[a-zA-Z]+                       { yylval.string = strdup(yytext); return WORD; }
+.                               { return (int)yytext[0]; }
+%%
diff --git a/src/cfgparse.y b/src/cfgparse.y
new file mode 100644
index 00000000..4b7224b5
--- /dev/null
+++ b/src/cfgparse.y
@@ -0,0 +1,379 @@
+%{
+#include <stdio.h>
+#include <string.h>
+#include <xcb/xcb.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#include "data.h"
+#include "config.h"
+#include "i3.h"
+#include "util.h"
+#include "queue.h"
+#include "table.h"
+
+extern int yylex(void);
+extern FILE *yyin;
+
+int yydebug = 1;
+
+void yyerror(const char *str) {
+        fprintf(stderr,"error: %s\n",str);
+}
+
+int yywrap() {
+        return 1;
+}
+
+void parse_file(const char *f) {
+        SLIST_HEAD(variables_head, Variable) variables = SLIST_HEAD_INITIALIZER(&variables);
+        int fd, ret, read_bytes = 0;
+        struct stat stbuf;
+        char *buf;
+        FILE *fstr;
+        char buffer[1026], key[512], value[512];
+
+        if ((fd = open(f, O_RDONLY)) == -1)
+                die("Could not open configuration file: %s\n", strerror(errno));
+
+        if (fstat(fd, &stbuf) == -1)
+                die("Could not fstat file: %s\n", strerror(errno));
+
+        buf = smalloc(stbuf.st_size * sizeof(char));
+        while (read_bytes < stbuf.st_size) {
+                if ((ret = read(fd, buf + read_bytes, (stbuf.st_size - read_bytes))) < 0)
+                        die("Could not read(): %s\n", strerror(errno));
+                read_bytes += ret;
+        }
+
+        if (lseek(fd, 0, SEEK_SET) == (off_t)-1)
+                die("Could not lseek: %s\n", strerror(errno));
+
+        if ((fstr = fdopen(fd, "r")) == NULL)
+                die("Could not fdopen: %s\n", strerror(errno));
+
+        while (!feof(fstr)) {
+                if (fgets(buffer, 1024, fstr) == NULL) {
+                        if (feof(fstr))
+                                break;
+                        die("Could not read configuration file\n");
+                }
+
+                /* sscanf implicitly strips whitespace. Also, we skip comments and empty lines. */
+                if (sscanf(buffer, "%s %[^\n]", key, value) < 1 ||
+                    key[0] == '#' || strlen(key) < 3)
+                        continue;
+
+                if (strcasecmp(key, "set") == 0) {
+                        if (value[0] != '$')
+                                die("Malformed variable assignment, name has to start with $\n");
+
+                        /* get key/value for this variable */
+                        char *v_key = value, *v_value;
+                        if ((v_value = strstr(value, " ")) == NULL)
+                                die("Malformed variable assignment, need a value\n");
+
+                        *(v_value++) = '\0';
+
+                        struct Variable *new = scalloc(sizeof(struct Variable));
+                        new->key = sstrdup(v_key);
+                        new->value = sstrdup(v_value);
+                        SLIST_INSERT_HEAD(&variables, new, variables);
+                        LOG("Got new variable %s = %s\n", v_key, v_value);
+                        continue;
+                }
+        }
+
+        /* For every custom variable, see how often it occurs in the file and
+         * how much extra bytes it requires when replaced. */
+        struct Variable *current, *nearest;
+        int extra_bytes = 0;
+        SLIST_FOREACH(current, &variables, variables) {
+                int extra = (strlen(current->value) - strlen(current->key));
+                char *next;
+                for (next = buf;
+                     (next = strcasestr(buf + (next - buf), current->key)) != NULL;
+                     next += strlen(current->key))
+                        extra_bytes += extra;
+        }
+
+        /* Then, allocate a new buffer and copy the file over to the new one,
+         * but replace occurences of our variables */
+        char *walk = buf, *destwalk;
+        char *new = smalloc((stbuf.st_size + extra_bytes) * sizeof(char));
+        destwalk = new;
+        while (walk < (buf + stbuf.st_size)) {
+                /* Find the next variable */
+                SLIST_FOREACH(current, &variables, variables)
+                        current->next_match = strcasestr(walk, current->key);
+                nearest = NULL;
+                int distance = stbuf.st_size;
+                SLIST_FOREACH(current, &variables, variables) {
+                        if (current->next_match == NULL)
+                                continue;
+                        if ((current->next_match - walk) < distance) {
+                                distance = (current->next_match - walk);
+                                nearest = current;
+                        }
+                }
+                if (nearest == NULL) {
+                        /* If there are no more variables, we just copy the rest */
+                        strncpy(destwalk, walk, (buf + stbuf.st_size) - walk);
+                        destwalk += (buf + stbuf.st_size) - walk;
+                        *destwalk = '\0';
+                        break;
+                } else {
+                        /* Copy until the next variable, then copy its value */
+                        strncpy(destwalk, walk, distance);
+                        strncpy(destwalk + distance, nearest->value, strlen(nearest->value));
+                        walk += distance + strlen(nearest->key);
+                        destwalk += distance + strlen(nearest->value);
+                }
+        }
+
+        yy_scan_string(new);
+
+        if (yyparse() != 0) {
+                fprintf(stderr, "Could not parse configfile\n");
+                exit(1);
+        }
+
+        free(new);
+        free(buf);
+}
+
+%}
+
+%union {
+        int number;
+        char *string;
+        struct Colortriple *color;
+	struct Assignment *assignment;
+}
+
+%token <number>NUMBER
+%token <string>WORD
+%token <string>STR
+%token <string>STR_NG
+%token <string>HEX
+%token TOKBIND
+%token TOKTERMINAL
+%token TOKCOMMENT
+%token TOKFONT
+%token TOKBINDSYM
+%token MODIFIER
+%token TOKCONTROL
+%token TOKSHIFT
+%token WHITESPACE
+%token TOKFLOATING_MODIFIER
+%token QUOTEDSTRING
+%token TOKWORKSPACE
+%token TOKSCREEN
+%token TOKASSIGN
+%token TOKSET
+%token TOKIPCSOCKET
+%token TOKEXEC
+%token TOKCOLOR
+%token TOKARROW
+
+%%
+
+lines: /* empty */
+        | lines WHITESPACE line
+        | lines line
+        ;
+
+line:
+        bind
+        | bindsym
+        | floating_modifier
+        | workspace
+        | assign
+        | ipcsocket
+        | exec
+        | color
+        | terminal
+        | font
+        | comment
+        ;
+
+comment:
+        TOKCOMMENT
+        ;
+
+command:
+        STR
+        ;
+
+bind:
+        TOKBIND WHITESPACE binding_modifiers NUMBER WHITESPACE command
+        {
+                printf("\tFound binding mod%d with key %d and command %s\n", $<number>3, $4, $<string>6);
+                Binding *new = scalloc(sizeof(Binding));
+
+                new->keycode = $<number>4;
+                new->mods = $<number>3;
+                new->command = sstrdup($<string>6);
+
+                TAILQ_INSERT_TAIL(&bindings, new, bindings);
+        }
+        ;
+
+bindsym:
+        TOKBINDSYM WHITESPACE binding_modifiers WORD WHITESPACE command
+        {
+                printf("\tFound symbolic mod%d with key %s and command %s\n", $<number>3, $4, $<string>6);
+                Binding *new = scalloc(sizeof(Binding));
+
+                new->symbol = sstrdup($4);
+                new->mods = $<number>3;
+                new->command = sstrdup($<string>6);
+
+                TAILQ_INSERT_TAIL(&bindings, new, bindings);
+        }
+        ;
+
+floating_modifier:
+        TOKFLOATING_MODIFIER WHITESPACE binding_modifiers
+        {
+                LOG("floating modifier = %d\n", $<number>3);
+                config.floating_modifier = $<number>3;
+        }
+        ;
+
+workspace:
+        TOKWORKSPACE WHITESPACE NUMBER WHITESPACE TOKSCREEN WHITESPACE screen workspace_name
+        {
+                int ws_num = $<number>3;
+                if (ws_num < 1 || ws_num > 10) {
+                        LOG("Invalid workspace assignment, workspace number %d out of range\n", ws_num);
+                } else {
+                        workspaces[ws_num - 1].preferred_screen = sstrdup($<string>7);
+                        if ($<string>8 != NULL)
+                                workspace_set_name(&(workspaces[ws_num - 1]), $<string>8);
+                }
+        }
+        ;
+
+workspace_name:
+        /* NULL */                      { $<string>$ = NULL; }
+        | WHITESPACE QUOTEDSTRING       { $<string>$ = $<string>2; }
+        | WHITESPACE STR                { $<string>$ = $<string>2; }
+        ;
+
+screen:
+        NUMBER              { asprintf(&$<string>$, "%d", $<number>1); }
+        | NUMBER 'x'        { asprintf(&$<string>$, "%d", $<number>1); }
+        | NUMBER 'x' NUMBER { asprintf(&$<string>$, "%dx%d", $<number>1, $<number>3); }
+        | 'x' NUMBER        { asprintf(&$<string>$, "x%d", $<number>2); }
+        ;
+
+assign:
+        TOKASSIGN WHITESPACE window_class WHITESPACE optional_arrow assign_target
+        {
+                printf("assignment of %s to %d\n", $<string>3, $<number>6);
+
+		struct Assignment *new = $<assignment>6;
+		new->windowclass_title = strdup($<string>3);
+		TAILQ_INSERT_TAIL(&assignments, new, assignments);
+        }
+        ;
+
+assign_target:
+	NUMBER
+	{
+		struct Assignment *new = scalloc(sizeof(struct Assignment));
+		new->workspace = $<number>1;
+		new->floating = ASSIGN_FLOATING_NO;
+		$<assignment>$ = new;
+	}
+	| '~'
+	{
+		struct Assignment *new = scalloc(sizeof(struct Assignment));
+		new->floating = ASSIGN_FLOATING_ONLY;
+		$<assignment>$ = new;
+	}
+	| '~' NUMBER
+	{
+		struct Assignment *new = scalloc(sizeof(struct Assignment));
+		new->workspace = $<number>2;
+		new->floating = ASSIGN_FLOATING;
+		$<assignment>$ = new;
+	}
+	;
+
+window_class:
+        QUOTEDSTRING
+        | STR_NG
+        ;
+
+optional_arrow:
+        /* NULL */
+        | TOKARROW WHITESPACE
+        ;
+
+ipcsocket:
+        TOKIPCSOCKET WHITESPACE STR
+        {
+                config.ipc_socket_path = sstrdup($<string>3);
+        }
+        ;
+
+exec:
+        TOKEXEC WHITESPACE STR
+        {
+                struct Autostart *new = smalloc(sizeof(struct Autostart));
+                new->command = sstrdup($<string>3);
+                TAILQ_INSERT_TAIL(&autostarts, new, autostarts);
+        }
+        ;
+
+terminal:
+        TOKTERMINAL WHITESPACE STR
+        {
+                config.terminal = sstrdup($<string>3);
+                printf("terminal %s\n", config.terminal);
+        }
+        ;
+
+font:
+        TOKFONT WHITESPACE STR
+        {
+                config.font = sstrdup($<string>3);
+                printf("font %s\n", config.font);
+        }
+        ;
+
+
+color:
+        TOKCOLOR WHITESPACE colorpixel WHITESPACE colorpixel WHITESPACE colorpixel
+        {
+                struct Colortriple *dest = $<color>1;
+
+                dest->border = $<number>3;
+                dest->background = $<number>5;
+                dest->text = $<number>7;
+        }
+        ;
+
+colorpixel:
+        '#' HEX         { $<number>$ = get_colorpixel(global_conn, $<string>2); }
+        ;
+
+
+binding_modifiers:
+        /* NULL */                               { $<number>$ = 0; }
+        | binding_modifier
+        | binding_modifiers '+' binding_modifier { $<number>$ = $<number>1 | $<number>3; }
+        | binding_modifiers '+'                  { $<number>$ = $<number>1; }
+        ;
+
+binding_modifier:
+        MODIFIER        { $<number>$ = $<number>1; }
+        | TOKCONTROL    { $<number>$ = BIND_CONTROL; }
+        | TOKSHIFT      { $<number>$ = BIND_SHIFT; }
+        ;
diff --git a/src/config.c b/src/config.c
index dd2f70c1..ffc8b7ed 100644
--- a/src/config.c
+++ b/src/config.c
@@ -28,6 +28,8 @@
 
 Config config;
 
+bool config_use_lexer = false;
+
 /*
  * This function resolves ~ in pathnames.
  *
@@ -226,6 +228,25 @@ void load_configuration(xcb_connection_t *conn, const char *override_configpath,
         config.bar.urgent.background = get_colorpixel(conn, "#900000");
         config.bar.urgent.text = get_colorpixel(conn, "#ffffff");
 
+        if (config_use_lexer) {
+                /* Yes, this will be cleaned up soon. */
+                if (override_configpath != NULL) {
+                        parse_file(override_configpath);
+                } else {
+                        FILE *handle;
+                        char *globbed = glob_path("~/.i3/config");
+                        if ((handle = fopen(globbed, "r")) == NULL) {
+                                if ((handle = fopen("/etc/i3/config", "r")) == NULL) {
+                                        die("Neither \"%s\" nor /etc/i3/config could be opened\n", globbed);
+                                } else {
+                                        parse_file("/etc/i3/config");
+                                }
+                        } else {
+                                parse_file(globbed);
+                        }
+                }
+        } else {
+
         FILE *handle;
         if (override_configpath != NULL) {
                 if ((handle = fopen(override_configpath, "r")) == NULL)
@@ -508,9 +529,6 @@ void load_configuration(xcb_connection_t *conn, const char *override_configpath,
                 grab_all_keys(conn);
         fclose(handle);
 
-        REQUIRED_OPTION(terminal);
-        REQUIRED_OPTION(font);
-
         while (!SLIST_EMPTY(&variables)) {
                 struct Variable *v = SLIST_FIRST(&variables);
                 SLIST_REMOVE_HEAD(&variables, variables);
@@ -518,6 +536,10 @@ void load_configuration(xcb_connection_t *conn, const char *override_configpath,
                 free(v->value);
                 free(v);
         }
+        }
+
+        REQUIRED_OPTION(terminal);
+        REQUIRED_OPTION(font);
 
         /* Set an empty name for every workspace which got no name */
         for (int i = 0; i < 10; i++) {
diff --git a/src/mainx.c b/src/mainx.c
index db3d184a..329aae29 100644
--- a/src/mainx.c
+++ b/src/mainx.c
@@ -165,7 +165,7 @@ int main(int argc, char *argv[], char *env[]) {
 
         start_argv = argv;
 
-        while ((opt = getopt_long(argc, argv, "c:vah", long_options, &option_index)) != -1) {
+        while ((opt = getopt_long(argc, argv, "c:vahl", long_options, &option_index)) != -1) {
                 switch (opt) {
                         case 'a':
                                 LOG("Autostart disabled using -a\n");
@@ -177,6 +177,9 @@ int main(int argc, char *argv[], char *env[]) {
                         case 'v':
                                 printf("i3 version " I3_VERSION " © 2009 Michael Stapelberg and contributors\n");
                                 exit(EXIT_SUCCESS);
+                        case 'l':
+                                config_use_lexer = true;
+                                break;
                         default:
                                 fprintf(stderr, "Usage: %s [-c configfile] [-a] [-v]\n", argv[0]);
                                 fprintf(stderr, "\n");