tcl: classic programs — for-each-line, assert, with-temp-var (+3 tests, 228 total)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/tcl/tests/programs/assert.tcl

@@ -0,0 +1,13 @@
+proc assert {expr_str} {
+    set result [uplevel 1 [list expr $expr_str]]
+    if {!$result} {
+        error "Assertion failed: $expr_str"
+    }
+}
+
+set x 42
+assert {$x == 42}
+assert {$x > 0}
+set x 10
+assert {$x < 100}
+set x

lib/tcl/tests/programs/for-each-line.tcl

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+proc for-each-line {var lines body} {
+    foreach item $lines {
+        uplevel 1 [list set $var $item]
+        uplevel 1 $body
+    }
+}
+
+# Usage: accumulate lengths of each "line"
+set total 0
+for-each-line line {hello world foo} {
+    incr total [string length $line]
+}
+set total

lib/tcl/tests/programs/with-temp-var.tcl

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+proc with-temp-var {varname tempval body} {
+    upvar 1 $varname v
+    set saved $v
+    set v $tempval
+    uplevel 1 $body
+    set v $saved
+}
+
+set x 100
+with-temp-var x 999 {
+    set captured $x
+}
+list $x $captured