Switch by Zed Lopez

Version 2/220401

"A switch statement. Tested with 6M62."
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Doesn't fall through. Sorry, Duff's Device fans.
If you include a default case, it must be the last thing.
Chapter Changelog
2/220329 cleanup, no longer track kind in state array, use fewer temp vars
Example: * Switch
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Play "switch"

"switch"
Include Switch by Zed Lopez.
Lab is a room.
xyz is initially 3.
To decide what text is switchcat (T - a text):
 if switch T begin;
    if / "dog" /, decide on switchcat "cat";
    if == "cat" begin;
      if switch xyz begin;
        if range 4 to 8, decide on "blue";
        if range 2 to 3, decide on "red";
        if > 5, decide on "moo";
        if < 4, decide on "baa";
        if == 3, decide on "yow";
        if default case, decide on "blah";
      end if;
    end if;
    if / "c.t?" /, decide on "meow.";
 end if;
 decide on "?";
when play begins:
 if switch 2 begin;
    if == 1, say "yow!";
    if < 3, say switchcat "dog";
    if default case, say "nothing.";
 end if;
Version 2/220401 of Switch by Zed Lopez begins here.
"A switch statement. Tested with 6M62."
Include (-
 Constant SWITCH_ARRAY_WIDTH = 3;
 Constant SWITCH_VAR = 1;
 Constant SWITCH_CMP = 2;
 Constant SWITCH_STATE = 3;
 Global switch_stack_pointer = 0;
 -) after "Definitions.i6t".
Use switch stack size of at least 250 translates as (- Constant SWITCH_STACK_SIZE = {N}; -).
default is always true.
Include (-
 Array SwitchStack table SWITCH_ARRAY_WIDTH * SWITCH_STACK_SIZE;
[ pushSwitchStack s_var s_cmp s_state;
    switch_stack_pointer++;
    if (switch_stack_pointer == SWITCH_STACK_SIZE) {
      print "^*** Out of switch stack space of ", SWITCH_STACK_SIZE, "^";
      rfalse;
    }
    SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR) = s_var;
    SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP) = s_cmp;
    SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE) = s_state;
 ];
[ cmpFn kind;
    if (kind == NUMBER_TY) return SwSignedCompare;
    return KOVComparisonFunction(kind);
 ];
[ SwSignedCompare x y;
 if (x > y) return 1;
 if (x < y) return -1;
 return 0;
 ];
-);
To if switch (v - a value of kind K) begin -- end loop:
    (-
    pushSwitchStack({v}, cmpFn({-strong-kind:K}), 1);
    if (1) {-block}
    switch_stack_pointer--;
     -)
To if == (v2 - a value) begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    {-my:2} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP);
    if ({-my:2}({-my:1},{v2}) == 0) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -)
To if < (v2 - a value) begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    {-my:2} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP);
   if ({-my:2}({-my:1},{v2}) < 0) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -)
To if > (v2 - a value) begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    {-my:2} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP);
   if ({-my:2}({-my:1},{v2}) > 0) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -)
To if <= (v2 - a value) begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    {-my:2} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP);
   if ({-my:2}({-my:1},{v2}) <= 0) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -)
To if >= (v2 - a value) begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    {-my:2} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP);
    if ({-my:2}({-my:1},{v2}) >= 0) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -)
To if <>/!- (v2 - a value) begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    {-my:2} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP);
    if ({-my:2}({-my:1},{v2}) =~ 0) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -)
To if range (v2 - a value) to (v3 - a value) begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    {-my:2} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP);
    if (({-my:2}({-my:1},{v2}) >= 0) && ({-my:2}({-my:1},{v3}) <= 0)) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -)
To if in (L - a list of values of kind K) begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    if (LIST_OF_TY_FindItem({-by-reference:L}, {-my:1})) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -)

To if / (R - a text) / begin -- end loop:
    (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
    {-my:1} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_VAR);
    {-my:2} = SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_CMP);
    if (TEXT_TY_Replace_RE(REGEXP_BLOB,{-my:1},{-by-reference:R},0,{phrase options})) {
      switch_stack_pointer--;
      if (1) {-block};
      pushSwitchStack({-my:1},{-my:2},0);
      }
    }
 -).
To if (v - a value) case begin -- end loop: (-
    if (SwitchStack-->(switch_stack_pointer * SWITCH_ARRAY_WIDTH + SWITCH_STATE)) {
      switch_stack_pointer--;
      if (1) {-block}
      switch_stack_pointer++; ! don't bother maintaining values, we're done
 }
-)
Switch ends here.