idl-api: stdlib candidates, add a bunch of text formatting functions

idl/idl_api.ysl2

@@ -17,6 +17,80 @@ def "func:exists" {
     }
 }
 
+def "func:repeat_until" {
+    param "str";
+    param "count";
+
+    choose {
+        when "string-length($str) < $count" {
+            result "func:repeat_until(concat($str, $str), $count)";
+        } otherwise {
+            result "substring($str, 0, $count+1)";
+        }
+    }
+}
+
+def "func:indent" {
+    param "content";
+    param "indent_count";
+    param "indent_char", "'\t'";
+    result > «func:repeat_until($indent_char, $indent_count)»«$content»
+}
+
+def "func:paragraph_block" {
+    param "content";
+    param "nth", "80";
+    param "wrap_char", "'\n'";
+    const "cont_oneline", "translate($content, '\n', ' ')";
+    result > «func:line_wrap($cont_oneline, $nth, $wrap_char)»
+}
+
+def "func:line_wrap" {
+    param "content";
+    param "nth", "80";
+    param "wrap_char", "'\n'";
+    const "sep_char", "''";
+    const "nth_minus_dash", "$nth - string-length($sep_char)";
+    const "ret", "substring($content, 0, $nth_minus_dash)";
+    const "remainder", "substring($content, $nth_minus_dash)";
+
+    choose {
+        when "string-length($remainder) > $nth_minus_dash" {
+            result > «$ret»«$sep_char»«$wrap_char»«func:line_wrap($remainder, $nth)»
+        } otherwise {
+            result > «$ret»«$sep_char»«$wrap_char»«$remainder»
+        }
+    }
+}
+
+def "func:column_paragraph" {
+    param "title";
+    param "content";
+    param "max_width";
+    result call "column_paragraph"
+        with "title", "$title",
+        with "content", "$content",
+        with "max_width", "$max_width";
+}
+function "column_paragraph" {
+    param "title";
+    param "content";
+    param "max_width";
+    const "title_width", "string-length($title)";
+    const "cont_width", "$max_width - $title_width";
+
+    const "cont_wrapped", "func:paragraph_block($content, $cont_width)";
+    for "str:split($cont_wrapped, '\n')" {
+        const "line", ".";
+        choose {
+            when "position() = 1"
+                | «$title»«func:indent($line,1,' ')»
+            otherwise
+                | «func:indent($line, $title_width+1,' ')»
+        }
+    }
+}
+
 // ----------------------------------------------------------------------
 // idl-api (ysl2)
 // ----------------------------------------------------------------------
@@ -105,7 +179,6 @@ def "func:idl_type_is_generic" {
     result "contains($idltype,'<') and contains($idltype,'>')"
 }
 
-
 // TODO: generic is actually not a typekid, this should return the generic typekind like list/map/pair
 def "func:idl_type_get_typekind_of_type" {
     param "idltype";