Make repeat statement support return, break and continue

NEWS.md

@@ -1,5 +1,11 @@
 # Genoa Banner Creator project news
 
+## [0.5 alpha] - unreleased
+
+### Changed
+
+* The repeat statement now supports return, break and continue.
+
 ## [0.4 alpha] - 2023-09-14
 
 ### Added

README.md

@@ -6,7 +6,7 @@ Rationale: I make vector art by hand (see the Pocket Guide to Writing SVG, by Jo
 
 ## Availability
 
-As of September 2023, Genoa is at a very early alpha stage: incomplete, undocumented and probably buggy. Use at your own risk. System requirements:
+As of September 2023, Genoa is at a very early alpha stage: incomplete, poorly documented and probably buggy. Use at your own risk. System requirements:
 
 - to run from source, Tcl/Tk 8.6 with tklib
 - screen resolution:
@@ -15,7 +15,7 @@ As of September 2023, Genoa is at a very early alpha stage: incomplete, undocume
 
 ## Usage
 
-Genoa is powered by a little language based on Tcl. Right now it can generate its own promotional banner, like this:
+Genoa is powered by a little language based on Tcl. For example its own promotional banner is defined like this:
 
 ```tcl
 # The viewport declaration can be anywhere.
@@ -39,7 +39,7 @@ color darkblue; circles 400 400
 
 font "Noto Sans"; size 48
 color white; set j 0
-foreach i {GENERATE ORIGINAL ART} {
+foreach i "GENERATE ORIGINAL ART" {
 	incr j 64
 	text 225 [+ 225 $j] $i
 }

genoa.tcl

@@ -54,7 +54,20 @@ interp create -safe runner
 runner eval {
 	proc repeat {times code} {
 		for {set i 0} {$i < $times} {incr i} {
-			uplevel 1 $code
+			set ret [catch {uplevel 1 $code} message]
+			switch $ret {
+				0 {}
+				1 {
+					return -code error \
+						-errorinfo $::errorInfo \
+						-errorcode $::errorCode \
+						$message 
+				}
+				2 { return -code return $message }
+				3 { break }
+				4 {}
+				default { return -code $code $message }
+			}
 		}
 	}
 	namespace path {::tcl::mathop ::tcl::mathfunc}