From 4e7590226ba3f9f1f70e582e5b16d1664bf57c83 Mon Sep 17 00:00:00 2001
From: Scott Richmond <kredati@users.noreply.github.com>
Date: Sun, 19 Jun 2022 14:52:38 -0400
Subject: [PATCH] Copypasta splat patterns to dict, struct, tuple in parser

---
 src/ludus/parser.clj | 46 ++++++++++++++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/src/ludus/parser.clj b/src/ludus/parser.clj
index fd1331e..7400444 100644
--- a/src/ludus/parser.clj
+++ b/src/ludus/parser.clj
@@ -522,7 +522,7 @@
                :token (current origin)
                :length (count ms)
                :members ms})
-            (panic parser "A splat my only appear once in a pattern, at the end of a pattern.")))
+            (panic parser "A splat my only appear once in a list pattern, at the end of the pattern.")))
 
         (::token/comma ::token/newline)
         (recur
@@ -548,11 +548,15 @@
          current_member nil]
     (let [curr (current parser)]
       (case (token-type parser)
-        ::token/rbrace (let [ms (add-member members current_member)]
-                         (assoc (advance parser) ::ast
-                           {::ast/type ::ast/dict
-                            :token (current origin)
-                            :members ms}))
+        ::token/rbrace
+        (let [ms (add-member members current_member)]
+          (if (not-any? #(= (::ast/type %) ::ast/splat) (drop-last ms))
+            (assoc (advance parser) ::ast
+              {::ast/type ::ast/tuple
+               :token (current origin)
+               :length (count ms)
+               :members ms})
+            (panic parser "A splat my only appear once in a dict pattern, at the end of the pattern.")))
 
         (::token/comma ::token/newline)
         (recur
@@ -565,6 +569,10 @@
         ::token/eof
         (panic (assoc origin ::errors (::errors parser)) "Unterminated dict pattern" ::token/eof)
 
+        ::token/splat
+        (let [splatted (parse-splat-pattern parser)]
+          (recur splatted members (::ast splatted)))
+
         ::token/word
         (if (not current_member)
           (let [parsed (parse-word parser) word (get-in parsed [::ast :word])]
@@ -585,11 +593,15 @@
          current_member nil]
     (let [curr (current parser)]
       (case (token-type parser)
-        ::token/rbrace (let [ms (add-member members current_member)]
-                         (assoc (advance parser) ::ast
-                           {::ast/type ::ast/struct
-                            :token (current origin)
-                            :members ms}))
+        ::token/rbrace
+                (let [ms (add-member members current_member)]
+          (if (not-any? #(= (::ast/type %) ::ast/splat) (drop-last ms))
+            (assoc (advance parser) ::ast
+              {::ast/type ::ast/tuple
+               :token (current origin)
+               :length (count ms)
+               :members ms})
+            (panic parser "A splat my only appear once in a struct pattern, at the end of the pattern.")))
 
         (::token/comma ::token/newline)
         (recur
@@ -602,6 +614,10 @@
         ::token/eof
         (panic (assoc origin ::errors (::errors parser)) "Unterminated struct pattern" ::token/eof)
 
+        ::token/splat
+        (let [splatted (parse-splat-pattern parser)]
+          (recur splatted members (::ast splatted)))
+
         ::token/word
         (if (not current_member)
           (let [parsed (parse-word parser) word (get-in parsed [::ast :word])]
@@ -625,11 +641,13 @@
       (case (token-type parser)
         ::token/rparen 
         (let [ms (add-member members current_member)]
+          (if (not-any? #(= (::ast/type %) ::ast/splat) (drop-last ms))
             (assoc (advance parser) ::ast
               {::ast/type ::ast/tuple
                :token (current origin)
                :length (count ms)
-               :members ms}))
+               :members ms})
+            (panic parser "A splat my only appear once in a tuple pattern, at the end of the pattern.")))
           
 
         (::token/comma ::token/newline)
@@ -643,6 +661,10 @@
         ::token/eof
         (panic (assoc origin ::errors (::errors parser)) "Unterminated tuple" ::token/eof)
 
+        ::token/splat
+        (let [splatted (parse-splat-pattern parser)]
+          (recur splatted members (::ast splatted)))
+
         (let [parsed (parse-pattern parser)]
           (recur parsed members (::ast parsed)))))))