Data update

Task/Parsing-RPN-calculator-algorithm/Crystal/parsing-rpn-calculator-algorithm.cr

@@ -0,0 +1,26 @@
+def rpn_calc (tokens)
+  stack = [] of Float64
+  tokens.each do |token|
+    if token.is_a?(Float64)
+      stack.push token
+    else
+      x = stack.pop
+      y = stack.pop
+      case token
+      when "+" then stack.push(y + x)
+      when "-" then stack.push(y - x)
+      when "*" then stack.push(y * x)
+      when "/" then stack.push(y / x)
+      when "^" then stack.push(y ** x)
+      else raise "unknown operator: #{token}"
+      end
+    end
+    puts "%4s  %s" % {token, stack}
+  end
+end
+
+def tokenize (s)
+  s.split.map {|t| t.to_f rescue t }
+end
+
+rpn_calc tokenize "3 4 2 * 1 5 - 2 3 ^ ^ / +"

Task/Parsing-RPN-calculator-algorithm/Pluto/parsing-rpn-calculator-algorithm.pluto

@@ -0,0 +1,33 @@
+require "queue"
+local fmt = require "fmt"
+
+local function rpn_calculate(expr)
+    assert(#expr > 0, "expression cannot be empty")
+    print($"For expression = {expr}\n")
+    print("Token           Action             Stack")
+    local tokens = expr:split(" "):filter(|t| -> #t > 0):reorder()
+    local stk = new stack()
+    for tokens as token do
+        local d = tonumber(token)
+        if d then
+            stk:push(d)
+            fmt.print(" %d     Push num onto top of stack  %s", d, fmt.swrite(stk:toarray()))
+        elseif #token > 1 or !(token in "+-*/^") then
+            error($"{token} is not a valid token.")
+        elseif stk:size() < 2 then
+            error("Stack contains too few operands.")
+        else
+            local d1 = stk:pop()
+            local d2 = stk:pop()
+            stk:push(token == "+" ? d2 + d1 :
+                     token == "-" ? d2 - d1 :
+                     token == "*" ? d2 * d1 :
+                     token == "/" ? d2 / d1 : d2 ^ d1)
+            fmt.print(" %s     Apply op to top of stack    %s", token, fmt.swrite(stk:toarray()))
+        end
+    end
+    fmt.print("\nThe final value is %0.14g", stk:pop())
+end
+
+local expr = "3 4 2 * 1 5 - 2 3 ^ ^ / +"
+rpn_calculate(expr)

Task/Parsing-RPN-calculator-algorithm/Red/parsing-rpn-calculator-algorithm.red

@@ -0,0 +1,21 @@
+Red [ "RPN Eval - Hinjo, July 25, 2025" ]
+rpn-exec: func [exp [string!]] [
+    stack: copy []
+    blk: load exp ; convert into block
+    foreach tok blk [
+        print [mold stack tok]
+        case [
+            number? tok [append stack tok]
+            find [+ - * / ^] tok [
+                if (length? stack) < 2 [
+                    print "Error: Two operands required!" exit ]
+                if tok = '^ [tok: '**]
+                b: take/last stack
+                a: take/last stack
+                append stack do compose [a (tok) b]
+            ]
+        ]
+    ]
+]
+; in Red, "^" is an escape char, so, it must be written as ^^
+rpn-exec "3 4 2 * 1 5 - 2 3 ^^ ^^ / +"