I am not sure, if I understand your question and what you want to achieve, but if you are looking for all the ascii representation of the chars you can get that with

asciis: [] parse teststring [some [set a alpha (append asciis to-integer a )| skip]] == true >> asciis == [116 104 105 115 105 115 106 117 115 116 114 97 110 100 111 109 114 97 109 98 108 105 110 103 116 111 116 101 115 116 112 97 114 115 105 110 103] 

some is one of the available words responsible for the looping

I am not sure, if I understand your question and what you want to achieve, but if you are looking for all the ascii representation of the chars you can get that with

asciis: [] parse teststring [some [set a alpha (append asciis to-integer a )| skip]] == true >> asciis == [116 104 105 115 105 115 106 117 115 116 114 97 110 100 111 109 114 97 109 98 108 105 110 103 116 111 116 101 115 116 112 97 114 115 105 110 103] 

some is one of the available words responsible for the looping

There are some issues in your trial. It would give some errors before doing any conversion. text2 is probably declared before. to alpha would give an empty string "" as you try to copy up to the first alpha character. Remember to goes up to and not including the target. You can not convert an empty string to a character. If we assume until now no error occurred, then you are still in front of your string and you go straight to the end of your string.

Some documentation about Red parse. see Iteration about looping

You can debug your parsing either with parse-trace or just put a simple (probe text) after the part of your rule you want to investigate: