WIP

apps/app_analyze_fn.lua

@@ -8,7 +8,7 @@ local expr   = require 'expressiontree'
 local sym    = require 'ti.sym'
 
 local function each_result(str, fn)
-   local tokens = lexer.tokenize(eval(str))
+   local tokens = lexer.tokenize(str)
    local e = tokens and expr.from_infix(tokens)
    if e then
       if e.text == '{' or e.text == 'or' or e.text == 'and' then
@@ -22,15 +22,17 @@ local function each_result(str, fn)
 end
 
 local function run_analyze(stack)
-  local fn, low, high = table.unpack(ask_n(3), { title = "Analyze ..." })
+  local fn, low, high = table.unpack(ask_n(3, { title = "Analyze ..." }))
   local var = "x"
 
   local with_str = nil
   if low:len() ~= 0 then
-    with_str = (with_str or "|") .. low  .."<" .. var
+    with_str = (with_str and with_str .. " and ") or "|"
+    with_str = with_str .. low  .. ">=" .. var
   end
   if high:len() ~= 0 then
-    with_str = (with_str or "|") .. var .."<" .. high
+    with_str = (with_str and with_str .. " and ") or "|"
+    with_str = with_str .. var .. "<=" .. high
   end
 
   local function get_zeros(fn, bounds)
@@ -41,19 +43,38 @@ local function run_analyze(stack)
                 end)
     return tab
   end
+
+  local function is_zero(fn, at)
+    return math.evalStr(string.format("(%s|%s=%s)=0", fn, var, at)) == "true"
+  end
+
+  local function has_sign_change(fn, at, delta)
+    local delta = "0.000001"
+    local is_neg_0 = math.evalStr(string.format("(%s|%s=%s-%s)<0", fn, var, at, delta)) == "true"
+    local is_neg_1 = math.evalStr(string.format("(%s|%s=%s+%s)<0", fn, var, at, delta)) == "true"
+    if is_neg_0 ~= is_neg_1 then
+      return (not is_neg_0 and is_neg_1) and -1 or 1
+    end
+    return 0
+  end
+
+  local results = {}
 
   local zeros = get_zeros(fn, with_str)
+  if zeros and #zeros > 0 then
+    table.insert(results, {title="Zeros", result="*zeros"})
+
+    for _, v in ipairs(zeros) do
+      local x = v:infix_string()
+      local y = math.evalStr(string.format("%s|%s=%s", fn, var, x))
+      table.insert(results, {title=string.format("%s=%s (%s|%s)", var, x, x, y), result=x})
+    end
+  end
+
+
   local r = choice({
     title = 'Results',
-    items = (function()
-      local list = {}
-      for i, v in ipairs(zeros) do
-        table.insert(list, {
-          title=string(v), result=i
-        })
-      end
-      return list
-    end)()
+    items = results
   })
 end