add SOURCE-ID

diff --git a/README.md b/README.md
index ffa1054ba265bd95a88f0443f06a86442d48d4b5..0d08ba3e5d0d5ba95915024d9891a9cf0676debe 100644 (file)
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ Alee Forth uses the [Forth 2012 test suite](https://github.com/gerryjackson/fort
 **Missing** core extension words:
 
 ```
-PARSE-NAME REFILL RESTORE-INPUT S\" SAVE-INPUT SOURCE-ID
+PARSE-NAME REFILL RESTORE-INPUT S\" SAVE-INPUT
 ```
 
 ## Building

diff --git a/forth/core-ext.fth b/forth/core-ext.fth
index 0c263d940179f4c39af06a6ec1ca3539073cdd99..8bc83bead8207570beb38b2e01a157b1085419e7 100644 (file)
--- a/forth/core-ext.fth
+++ b/forth/core-ext.fth
@@ -74,3 +74,4 @@
             rot dup >r c! r> char+ swap repeat
             2drop r> tuck - ;
 
+: source-id _source @ _begin < if 0 else -1 then ;