track the filename of an input buffer

this also includes some slightly better facilities for handling temporary strings

Change-Id: Idf5e6fd8ade675d7ceb73264d10895fe8da578d6
Force-Push: yes

1 files changed, 30 insertions, 0 deletions

diff --git a/language/dynamic/dynamic.e b/language/dynamic/dynamic.e
index 270e860..677a180 100644
--- a/language/dynamic/dynamic.e
+++ b/language/dynamic/dynamic.e
@@ -361,6 +361,29 @@
   dup dup stringlen 1+ + 8 packalign here ! ;
 
 
+~   Tests whether a string pointer is equal to the current value of "here".
+~ If it is, the string is in the temporary allocation space.
+~
+~   This is not a comprehensive test; there are other ways the string could be
+~ temporary, such as being part of a larger data structure which is temporary,
+~ or being a substring of a longer string, without itself being right at the
+~ start of the scratch space. However, the most common way to wind up with a
+~ temporary string is by using the string-literal syntax in immediate mode,
+~ and a string allocated that way will always pass this test.
+~
+~ (string pointer -- boolean)
+: is-temporary-string here @ = ;
+
+~   Calls allocate-string if and only if the string it's given passes
+~ is-temporary-string. This function is idempotent, since the string will no
+~ longer be at "here" after allocating it, so it's safe to call on a parameter
+~ you've received that you don't know where it came from.
+~
+~ (string pointer -- string pointer)
+: allocate-string-if-temporary
+  dup is-temporary-string { allocate-string } if ;
+
+
 ~   Allocate space by incrementing "here", and output a word entry header in
 ~ it. Also add it to the "latest" linked list. Use zero as the flag values;
 ~ accept a string pointer on the stack and use its contents as the name.
@@ -558,3 +581,10 @@
 ~ (value -- )
 : literal lit lit , , ;
 
+~   We also have the same thing but for string literals. This one is a bit
+~ more involved, and less often needed, but it saves trouble when it does come
+~ up.
+~
+~ (string pointer --)
+: literal-string lit litstring , here @ swap packstring 8 packalign here ! ;
+