initial commit of an f-string function

1 files changed, 35 insertions, 0 deletions

diff --git a/libs/fstring.neb b/libs/fstring.neb
new file mode 100644
index 0000000..5edddca
--- /dev/null
+++ b/libs/fstring.neb
@@ -0,0 +1,35 @@
+
+; bugs:
+;#16> (fmt "{x} x {")
+;exception! <class 'NameError'> name 'ev' is not defined
+
+
+(func fmt :string (inp :string)
+    ; need two variables
+    ; 1. the current processed string
+    ; 2. the neb code to run
+    ;
+    ; algorithm
+    ;  - read characters one by one, adding to result
+    ;  - if reach a {
+    ;     - read characters one by one, adding to neb code
+    ;     - when reach }, try to execute the neb code, 
+    ;       then append to the end of the result
+    ; - if the end of the string is successfully reached, return the result
+
+    (func brace-parse :[:string] (str :string cur :string)
+        ; returns (remaining value)
+        (if (eq? "}" (first-char str))
+            (list (rest-char str) (->string (eval (parse-neb cur))))
+            (brace-parse (rest-char str) (concat cur (first-char str)))))
+
+    (func inner-parse (str cur)
+        (branch
+            ((eq? 0 (length str)) cur)
+            ((eq? "{" (first-char str))
+                (block
+                    (def tmp (brace-parse (rest-char str) ""))
+                    (inner-parse (first tmp) (concat cur (first (rest tmp))))))
+            (#true (inner-parse (rest-char str) (concat cur (first-char str))))))
+
+    (inner-parse inp ""))