Add not_found_in_spec.md

not_found_in_spec.md

@@ -0,0 +1,82 @@
+While the [spec.html](https://wy-lang.org/spec.html) on the official website as of 11:07 July 27, 2020 (UTC) gives you a good enough approximation on how wenyan-lang works, there nevertheless seems to be some discrepancies between the spec.html and the current official implementation. Here I will list what I encountered while writing this transpiler.
+
+## keywords lacking in spec.html
+
+* 或若
+* 若其然者
+* 若其不然者
+* 乃止是遍
+
+## treatment of name_single_statement following statements
+While treated as part of a statement in many syntactic rules, such as
+
+```
+reference_statement         : '夫' data ('之' (STRING_LITERAL|INT_NUM|'其餘'|IDENTIFIER|'長'))? name_single_statement? ;
+```
+
+there actually is no need to handle `name_single_statement` to be part of a `reference_statement`.
+
+```
+加二以四。夫「丙」。名之曰「戊」曰「己」。
+```
+
+compiles to
+
+```
+const _ans1 = 2 + 4;
+const _ans2 = BING3;
+var WU4 = _ans1;
+var JI3 = _ans2;
+```
+
+, and thus it must be that the optional `name_single_statement` can just as validly treated as a separate entity that can be replaced by a `name_single_statement`.
+
+However, note that
+
+```
+加二以三。有數九。名之曰「酒數」曰「亜」。
+```
+
+compiles to
+
+```
+const _ans1 = 2 + 3;
+var JIU3SHU4 = 9;
+```
+
+and that `有數九。` does not compile. Thus, while the spec says
+
+```
+init_define_statement       : '有' TYPE data (name_single_statement)? ;
+```
+
+The `name_single_statement` is not optional; and if a `name_multi_statement` comes, it is cropped to a `name_single_statement` and the remaining identifiers are silently ignored.
+
+## other differences
+
+### mod_math_statement
+
+spec:
+```
+mod_math_statement          : '除' (INT_NUM|FLOAT_NUM|IDENTIFIER|'其') preposition (INT_NUM|FLOAT_NUM|IDENTIFIER) POST_MOD_MATH_OP? ;
+```
+
+Actual behavior: seems to allow `INT_NUM|FLOAT_NUM|IDENTIFIER|'其'` in the second argument.
+
+### assign_statement
+
+spec:
+```
+assign_statement            : '昔之' IDENTIFIER ('之' (INT_NUM|STRING_LITERAL|IDENTIFIER))? '者' (('今' ((data ('之' INT_NUM)?)|'其') '是矣')|'今不復存矣') ;
+```
+
+Actual behavior: seems to allow `'之' (INT_NUM|STRING_LITERAL|IDENTIFIER|'長')` in the second argument.
+
+### for_enum_statement
+
+spec:
+```
+for_enum_statement          : FOR_START_ENUM  (INT_NUM|IDENTIFIER)  FOR_MID_ENUM statement* FOR_IF_END ;
+```
+
+Actual behavior: seems to allow `INT_NUM|IDENTIFIER|'其'` in the second argument.

src/lex/mod.rs

@@ -130,7 +130,7 @@ pub enum Lex {
     /// 乃得矣
     Nai3De2Yi3,
 
-    /// 乃止是遍
+    /// 乃止是遍; not found in spec.html
     Nai3Zhi3Shi4Bian4,
 
     /// 銜