coffee: Fix exception on literal empty list

Issue kanaka#190

Author: dubek

coffee/step3_env.coffee

@@ -22,6 +22,7 @@ eval_ast = (ast, env) ->
 EVAL = (ast, env) ->
   #console.log "EVAL:", printer._pr_str ast
   if !types._list_Q ast then return eval_ast ast, env
+  if ast.length == 0 then return ast
 
   # apply list
   [a0, a1, a2, a3] = ast

coffee/step4_if_fn_do.coffee

@@ -23,6 +23,7 @@ eval_ast = (ast, env) ->
 EVAL = (ast, env) ->
   #console.log "EVAL:", printer._pr_str ast
   if !types._list_Q ast then return eval_ast ast, env
+  if ast.length == 0 then return ast
 
   # apply list
   [a0, a1, a2, a3] = ast

coffee/step5_tco.coffee

@@ -24,6 +24,7 @@ EVAL = (ast, env) ->
  loop
   #console.log "EVAL:", printer._pr_str ast
   if !types._list_Q ast then return eval_ast ast, env
+  if ast.length == 0 then return ast
 
   # apply list
   [a0, a1, a2, a3] = ast

coffee/step6_file.coffee

@@ -24,6 +24,7 @@ EVAL = (ast, env) ->
  loop
   #console.log "EVAL:", printer._pr_str ast
   if !types._list_Q ast then return eval_ast ast, env
+  if ast.length == 0 then return ast
 
   # apply list
   [a0, a1, a2, a3] = ast

coffee/step7_quote.coffee

@@ -36,6 +36,7 @@ EVAL = (ast, env) ->
  loop
   #console.log "EVAL:", printer._pr_str ast
   if !types._list_Q ast then return eval_ast ast, env
+  if ast.length == 0 then return ast
 
   # apply list
   [a0, a1, a2, a3] = ast

coffee/step8_macros.coffee

@@ -49,6 +49,7 @@ EVAL = (ast, env) ->
   # apply list
   ast = macroexpand ast, env
   if !types._list_Q ast then return eval_ast ast, env
+  if ast.length == 0 then return ast
 
   [a0, a1, a2, a3] = ast
   switch a0.name

coffee/step9_try.coffee

@@ -49,6 +49,7 @@ EVAL = (ast, env) ->
   # apply list
   ast = macroexpand ast, env
   if !types._list_Q ast then return eval_ast ast, env
+  if ast.length == 0 then return ast
 
   [a0, a1, a2, a3] = ast
   switch a0.name

coffee/stepA_mal.coffee

@@ -49,6 +49,7 @@ EVAL = (ast, env) ->
   # apply list
   ast = macroexpand ast, env
   if !types._list_Q ast then return eval_ast ast, env
+  if ast.length == 0 then return ast
 
   [a0, a1, a2, a3] = ast
   switch a0.name