From b16625cf6797da68f9c3c82a48509c7697d01040 Mon Sep 17 00:00:00 2001
From: Aleteoryx <alyx@aleteoryx.me>
Date: Sat, 7 Dec 2024 16:15:48 -0500
Subject: 2024.7; could be more elegant, but it works

---
 2024/tcl/07.tcl | 42 ++++++++++++++++++------------------------
 1 file changed, 18 insertions(+), 24 deletions(-)

diff --git a/2024/tcl/07.tcl b/2024/tcl/07.tcl
index 9c96af9..9cc9ddd 100755
--- a/2024/tcl/07.tcl
+++ b/2024/tcl/07.tcl
@@ -5,31 +5,25 @@ setup 7
 
 puts {Part 1: Total of valid test lines}
 
-proc op_search {ops targ cur rest} {
-  # cursed, produces exprs of the form "$cur<op>$next == $targ || ..."
-  set e1 {}
-  foreach op $ops {
-    lappend e1 [string cat {$cur} $op {$next == $targ}]
-  }
-  set e1 [join $e1 " || "]
-  # cursed, produces exprs of the form "[_op_search $e1 $e2 $targ [expr {$cur<op>$next}] $rest] || ..."
-  set e2 {}
-  foreach op $ops {
-    lappend e2 [string cat \
-      {[_op_search $e1 $e2 $targ [expr } \
-      [list [string cat {$cur} $op {$next}]] \
-      {] $rest]}]
+proc op_search {targ cur rest} {
+  set rest [lassign $rest next]
+  if {$rest == {}} {
+    expr {$cur + $next == $targ || $cur * $next == $targ}
+  } else {
+    expr {[op_search $targ [expr {$cur + $next}] $rest] ||
+          [op_search $targ [expr {$cur * $next}] $rest]}
   }
-  set e2 [join $e2 " || "]
-
-  _op_search $e1 $e2 $targ $cur $rest
 }
-proc _op_search {e1 e2 targ cur rest} {
+proc op_search_cat {targ cur rest} {
   set rest [lassign $rest next]
   if {$rest == {}} {
-    expr $e1
+#    puts "leaf: $cur,$next // $targ"
+    expr {$cur + $next == $targ || $cur * $next == $targ || [string cat $cur $next] == $targ}
   } else {
-    expr $e2
+#    puts "branch: $cur,$next .. $rest // $targ"
+    expr {[op_search_cat $targ [expr {$cur + $next}] $rest] ||
+          [op_search_cat $targ [expr {$cur * $next}] $rest] ||
+          [op_search_cat $targ [string cat $cur $next] $rest]}
   }
 }
 
@@ -38,11 +32,11 @@ set cat_test_total 0
 foreach line $input {
   lassign [split $line :] targ nums
   set nums [lassign $nums first]
-  if [op_search {{ + } { * }} $targ $first $nums] {
+  if [op_search $targ $first $nums] {
     incr test_total $targ
   }
-  if [op_search {{ + } { * } {}} $targ $first $nums] {
-    incr test_total $targ
+  if [op_search_cat $targ $first $nums] {
+    incr cat_test_total $targ
   }
 }
 
@@ -51,4 +45,4 @@ puts "Total: $test_total"
 puts ""
 puts {Part 2: Total of valid test lines with || operator}
 
-puts "2: $"
+puts "Total: $cat_test_total"
-- 
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