ff2.c
reads thru thing
if layer, makes new layer of type
adds to aggregate

looks at line
if starts with '[' creates layer (new interface func?)
fgets line with 'this=this' in
calls

interface {
...
   params {
     { "this", PARAM_THIS },
     { "that", PARAM_THAT },
   },
   num params = 2,

}

set_param(VikLayer*l,gint type_id,gchar *stuff) { switch(type_id) {
case PARAM_THIS:
  layer_set_this(l,stuff);
case PARAM_THAT:
  l->that = atol(stuff)
} }

checks thru params strlen() check and strncmp()
good -> set param

*now*, what if I could use all this set_param stuff for dynamic dialog box creation?
and default (non-interactive) new layers?

param name     ID        explanation           type           widget type              min/min len               max/max len       default val
colorvelocity  VEL       lower velocity range  CUSTOM         CUSTOM
line_thickness THICK     Track Line Thickness  INT            SPINBUTTON               1                         15                1
# on read,  if outside range, gives error. 

special stuff like color velocity range?

union param_val {
  gchar *s;
  long l;
  double d;
}

color velocity range:
[     ]  to  [      ]

so we need a special get_widget_for_param() thingy.
then                 set_param_from_widget() -> gets widget data does its thing

tabs?
radio boxes? (names)

----

ff2.c

typedef struct {
  Stack *under;
  gpointer data;
} Stack;

void pop(Stack **stack) {
  Stack *tmp = (*stack)->under;
  g_free ( *stack );
  *stack = tmp;
}

void push(Stack **stack)
{
  Stack *tmp = g_malloc ( sizeof ( Stack ) );
  tmp->under = *stack;
  *stack = tmp;
}

/*
read thru file
if "[Layer Type="
  push(&stack)
  new default layer of type (str_to_type) (check interface->name)
if "[EndLayer]"
  VikLayer *vl = stack->data;
  pop(&stack);
  vik_aggregate_layer_add_layer(stack->data, vl);
if "[LayerData]"
  vik_layer_data ( VIK_LAYER_DATA(stack->data), f, vp );

*/