commit b97fd3c64faac53fdbdc8f0dcf2c145efc0ef2b7
Author: snaki <nk@kyouma.net>
Date:   Sun Aug 28 21:39:25 2022 +0200

    initial commit uwu

diff --git a/calc.lua b/calc.lua
new file mode 100755
index 0000000..d282c5d
--- /dev/null
+++ b/calc.lua
@@ -0,0 +1,111 @@
+#!/usr/bin/env lua
+
+function splitTokens(s)
+    local tokens = {}
+    for i in string.gmatch(s, '%w+') do 
+        table.insert(tokens, i) 
+    end
+    return tokens
+end
+
+PLUS = 'a'
+MINUS = 's'
+TIMES = 'm'
+DIVIDE = 'd'
+
+function isDash(token)
+    return token == PLUS or token == MINUS
+end
+
+function isDot(token)
+    return token == TIMES or token == DIVIDE
+end
+
+function parseNum(tokens)
+    local val = table.remove(tokens, 1)
+    val = tonumber(val)
+    return {
+        ['type'] = 'num',
+        ['num'] = val
+    }
+end
+
+function parseFactor(tokens)
+    local lhs = parseNum(tokens)
+    while isDot(tokens[1]) do
+        local op = table.remove(tokens, 1)
+        local rhs = parseNum(tokens)
+        lhs = {
+            ['type'] = 'op',
+            ['op'] = op,
+            ['lhs'] = lhs,
+            ['rhs'] = rhs
+        }
+    end
+    return lhs
+end
+
+function parseTerm(tokens)
+    local lhs = parseFactor(tokens)
+    while isDash(tokens[1]) do
+        local op = table.remove(tokens, 1)
+        local rhs = parseFactor(tokens)
+        lhs = {
+            ['type'] = 'op',
+            ['op'] = op,
+            ['lhs'] = lhs,
+            ['rhs'] = rhs,
+        }
+    end
+    return lhs
+end
+
+function parseExpr(tokens)
+    return parseTerm(tokens)
+end
+
+function eval(expr)
+    if expr['type'] == 'num' then
+        return expr['num']
+    elseif expr['type'] == 'op' then
+        local lval = eval(expr['lhs'])
+        local rval = eval(expr['rhs'])
+        if expr['op'] == PLUS then
+            return lval + rval
+        elseif expr['op'] == MINUS then
+            return lval - rval
+        elseif expr['op'] == TIMES then
+            return lval * rval
+        elseif expr['op'] == DIVIDE then
+            return lval / rval
+        else
+            print('invalid operator!')
+        end
+    else
+        print('invalid expr type!')
+    end
+end
+
+return eval(parseExpr(splitTokens(expr:toStringNoDot())))
+
+function printTree(expr, depth)
+    local indent = string.rep('  ', depth)
+    print(indent .. 'type: ' .. expr['type'])
+    if expr['type'] == 'num' then
+        print(indent .. 'num: ' .. expr['num'])
+    elseif expr['type'] == 'op' then
+        print(indent .. 'op: ' .. expr['op'])
+        print(indent .. 'lhs:')
+        printTree(expr['lhs'], depth + 1)
+        print(indent .. 'rhs:')
+        printTree(expr['rhs'], depth + 1)
+    else
+        print('invalid expr type!')
+    end
+end
+
+program = '1.a.2.m.3.s.4'
+tree = parseExpr(splitTokens(program))
+printTree(tree, 0)
+print('result: ', eval(tree))
+
diff --git a/pdns.lua b/pdns.lua
new file mode 100644
index 0000000..e2817fc
--- /dev/null
+++ b/pdns.lua
@@ -0,0 +1,79 @@
+; expr = qname:makeRelative(newDN('calc.cyfn.de.'))
+function splitTokens(s)
+    local tokens = {}
+    for i in string.gmatch(s, '%w+') do 
+        table.insert(tokens, i) 
+    end
+    return tokens
+end
+PLUS = 'a'
+MINUS = 's'
+TIMES = 'm'
+DIVIDE = 'd'
+function isDash(token)
+    return token == PLUS or token == MINUS
+end
+function isDot(token)
+    return token == TIMES or token == DIVIDE
+end
+function parseNum(tokens)
+    local val = table.remove(tokens, 1)
+    val = tonumber(val)
+    return {
+        ['type'] = 'num',
+        ['num'] = val
+    }
+end
+function parseFactor(tokens)
+    local lhs = parseNum(tokens)
+    while isDot(tokens[1]) do
+        local op = table.remove(tokens, 1)
+        local rhs = parseNum(tokens)
+        lhs = {
+            ['type'] = 'op',
+            ['op'] = op,
+            ['lhs'] = lhs,
+            ['rhs'] = rhs
+        }
+    end
+    return lhs
+end
+function parseTerm(tokens)
+    local lhs = parseFactor(tokens)
+    while isDash(tokens[1]) do
+        local op = table.remove(tokens, 1)
+        local rhs = parseFactor(tokens)
+        lhs = {
+            ['type'] = 'op',
+            ['op'] = op,
+            ['lhs'] = lhs,
+            ['rhs'] = rhs,
+        }
+    end
+    return lhs
+end
+function parseExpr(tokens)
+    return parseTerm(tokens)
+end
+function eval(expr)
+    if expr['type'] == 'num' then
+        return expr['num']
+    elseif expr['type'] == 'op' then
+        local lval = eval(expr['lhs'])
+        local rval = eval(expr['rhs'])
+        if expr['op'] == PLUS then
+            return lval + rval
+        elseif expr['op'] == MINUS then
+            return lval - rval
+        elseif expr['op'] == TIMES then
+            return lval * rval
+        elseif expr['op'] == DIVIDE then
+            return lval / rval
+        else
+            print('invalid operator!')
+        end
+    else
+        print('invalid expr type!')
+    end
+end
+return eval(parseExpr(splitTokens(expr:toStringNoDot())))