docs:

- change codes for MR and encoding

Readme.md

@@ -2,14 +2,16 @@
 
 Meow lang is a programming language that compiles to *catlet*, another language that is hard to read but easy to execute. Meow's syntax is easier to read than catlet, but meow and catlet are equivalent.
 
-(It's called *catlet* because the only available two keywords are `cat` and `let`)
+(It's called *catlet* because the only available two keywords are `cat` and `let`, *currently*)
 
 Its main design purpose is to do experiments with "string substitution".
 
 ## Formal Definition
 
 Currently the definition of substitution of strings are defined by the built-in `replace` function of `String`.
 
+It's not allowed to do $[X/""]Y$ (replace empty string with some string).
+
 ## Concepts
 
 There are **no** functions in Meow. Instead, we have *macros*. A macro is a piece of code that can be evaluated to a string.
@@ -42,6 +44,7 @@ hello world
 - [Syntax](./docs/Syntax.md)
 - [Encoding](./docs/Encoding.md)
 - [Double Substitution Lemma](./docs/DSL.md)
+- [Multiple Replacement](./docs/MR.md)
 
 ## Examples
 

docs/Encoding.md

@@ -23,38 +23,28 @@ We have to first implement the `encode` and `decode` macro to help us.
 
 Encoding means to encode a string into another string that has some special properties that we can use.
 
-We define it by this:
-
-$$
-\mathtt{encode}(s) = \mathtt{"\_\^{\,}"} + (\mathtt{["\backslash \backslash"/"\backslash"]["\backslash \$"/"\$"]["\backslash \^{\,}"/"\^{\,}"]}s) + \mathtt{"\_\$"}
-$$
-
-We can prove the following results:
-
-1. $|x|=1 \land x \neq \mathtt{"\backslash"} \Rightarrow $ $x\mathtt{"\^{\,}"} \not\subset \mathtt{["\backslash \backslash"/"\backslash"]["\backslash \$"/"\$"]["\backslash \^{\,}"/"\^{\,}"]}s$, $x\mathtt{"\$"} \not\subset \mathtt{["\backslash \backslash"/"\backslash"]["\backslash \$"/"\$"]["\backslash \^{\,}"/"\^{\,}"]}s$
-
 ## Code
 
 ```meow
 encode(s) {
     var rep = {
-        "\" = "\\";
         "$" = "\$";
-        "^" = "\^";
+        "#" = "\#";
+        "\" = "\\";
         s
     };
-    "_^"+ rep +"_$"
+    "#$"+ rep +"$#"
 }
 
 decode(s) {
     var rep = {
-        "_^" = "";
-        "_$" = "";
+        "$#" = "";
+        "#$" = "";
         s
     };
-    "\$" = "$";
-    "\^" = "^";
     "\\" = "\";
+    "\#" = "#";
+    "\$" = "$";
     rep
 }
 ```

docs/Multiple Replacement.md → docs/MR.md

@@ -20,9 +20,13 @@ First, we have to make sure that the multiple strings are all **independent**. O
 Implementation code for 2 strings:
 
 ```meow
+encat(x,y) {
+    {"#$"=""; x} + {"$#"=""; y}
+}
+
 enraw(s) {
-    "_^" = "";
-    "_$" = "";
+    "#$" = "";
+    "$#" = "";
     encode(s)
 }
 
@@ -32,11 +36,11 @@ enrep(s,x,y) {
 }
 
 rep2(s,x,xr,y,yr) {
-    var repx = enrep(encode(s),x,"x$");
-    var repy = enrep(repx,y,"y$");
+    var repx = enrep(encode(s),x,"x#");
+    var repy = enrep(repx,y,"y#");
     decode({
-        "x$" = enraw(xr);
-        "y$" = enraw(yr);
+        "x#" = enraw(xr);
+        "y#" = enraw(yr);
         repy
     })
 }

examples/syn.cat

@@ -19,7 +19,6 @@ mul x y = let "S" let 0 "" y x
 dr x y z = let y x let x y z
 encode s = cat cat "#$" let "$" "\$" let "#" "\#" let "\" "\\" s "$#"
 decode s = let "\\" "\" let "\#" "#" let "\$" "$" let "$#" "" let "#$" "" s
-encat x y = cat let "#$" "" x let "$#" "" y
 enraw s = let "#$" "" let "$#" "" encode s
 enrep s x y = let enraw x y s
 rep2 s x xr y yr = decode let "x#" enraw xr let "y#" enraw yr enrep enrep encode s x "x#" y "y#"

examples/syn.meow

@@ -74,10 +74,6 @@ decode(s) {
     rep
 }
 
-encat(x,y) {
-    {"#$"=""; x} + {"$#"=""; y}
-}
-
 enraw(s) {
     "#$" = "";
     "$#" = "";