Add forth exercise

config.json

@@ -538,6 +538,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "forth",
+        "name": "Forth",
+        "uuid": "eab77e91-52bf-497b-88a5-0404e11a64e4",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "strain",
         "name": "Strain",

exercises/practice/forth/.docs/instructions.append.md

@@ -0,0 +1,5 @@
+# Instructions append
+
+```exercism/note
+As Uiua does _not_ support putting functions on the stack, you won't be implementing user-defined words.
+```

exercises/practice/forth/.docs/instructions.md

@@ -0,0 +1,23 @@
+# Instructions
+
+Implement an evaluator for a very simple subset of Forth.
+
+[Forth][forth]
+is a stack-based programming language.
+Implement a very basic evaluator for a small subset of Forth.
+
+Your evaluator has to support the following words:
+
+- `+`, `-`, `*`, `/` (integer arithmetic)
+- `DUP`, `DROP`, `SWAP`, `OVER` (stack manipulation)
+
+Your evaluator also has to support defining new words using the customary syntax: `: word-name definition ;`.
+
+To keep things simple the only data type you need to support is signed integers of at least 16 bits size.
+
+You should use the following rules for the syntax: a number is a sequence of one or more (ASCII) digits, a word is a sequence of one or more letters, digits, symbols or punctuation that is not a number.
+(Forth probably uses slightly different rules, but this is close enough.)
+
+Words are case-insensitive.
+
+[forth]: https://en.wikipedia.org/wiki/Forth_%28programming_language%29

exercises/practice/forth/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "forth.ua"
+    ],
+    "test": [
+      "tests.ua"
+    ],
+    "example": [
+      ".meta/example.ua"
+    ]
+  },
+  "blurb": "Implement an evaluator for a very simple subset of Forth."
+}

exercises/practice/forth/.meta/example.ua

@@ -0,0 +1,24 @@
+Words  ← {"+" "-" "*" "/" "dup" "swap" "over" "drop"}
+Parse  ← ⊜□≠@\s.
+Number ← ⊂◇⋕
+UnaryOp! ← |2 ⨬(
+  ⍤"empty stack"
+| ⍜(↙1|^0)
+) ↧1⧻.
+BinaryOp! ← |2 ⨬(
+  ⍤"empty stack"
+| ⍤ "only one value on the stack"
+| ⍜(↙2|^0°⊟)
+) ↧2⧻.
+Op ← ⨬(
+  BinaryOp!+◌
+| BinaryOp!-◌
+| BinaryOp!×◌
+| BinaryOp!(⨬(⌊÷|⍤"divide by zero") =0.)◌
+| UnaryOp!(⊂.)◌
+| BinaryOp!(⊂:)◌
+| BinaryOp!(⊂⊂,)◌
+| UnaryOp!([]◌)◌
+| Number
+) ⊸(⊗⊙Words)
+Evaluate ← ⇌ ∧Op ⊙[] Parse ¯⌵

exercises/practice/forth/.meta/tests.toml

@@ -0,0 +1,188 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[9962203f-f00a-4a85-b404-8a8ecbcec09d]
+description = "parsing and numbers -> numbers just get pushed onto the stack"
+
+[fd7a8da2-6818-4203-a866-fed0714e7aa0]
+description = "parsing and numbers -> pushes negative numbers onto the stack"
+
+[9e69588e-a3d8-41a3-a371-ea02206c1e6e]
+description = "addition -> can add two numbers"
+
+[52336dd3-30da-4e5c-8523-bdf9a3427657]
+description = "addition -> errors if there is nothing on the stack"
+
+[06efb9a4-817a-435e-b509-06166993c1b8]
+description = "addition -> errors if there is only one value on the stack"
+
+[1e07a098-c5fa-4c66-97b2-3c81205dbc2f]
+description = "addition -> more than two values on the stack"
+
+[09687c99-7bbc-44af-8526-e402f997ccbf]
+description = "subtraction -> can subtract two numbers"
+
+[5d63eee2-1f7d-4538-b475-e27682ab8032]
+description = "subtraction -> errors if there is nothing on the stack"
+
+[b3cee1b2-9159-418a-b00d-a1bb3765c23b]
+description = "subtraction -> errors if there is only one value on the stack"
+
+[2c8cc5ed-da97-4cb1-8b98-fa7b526644f4]
+description = "subtraction -> more than two values on the stack"
+
+[5df0ceb5-922e-401f-974d-8287427dbf21]
+description = "multiplication -> can multiply two numbers"
+
+[9e004339-15ac-4063-8ec1-5720f4e75046]
+description = "multiplication -> errors if there is nothing on the stack"
+
+[8ba4b432-9f94-41e0-8fae-3b3712bd51b3]
+description = "multiplication -> errors if there is only one value on the stack"
+
+[5cd085b5-deb1-43cc-9c17-6b1c38bc9970]
+description = "multiplication -> more than two values on the stack"
+
+[e74c2204-b057-4cff-9aa9-31c7c97a93f5]
+description = "division -> can divide two numbers"
+
+[54f6711c-4b14-4bb0-98ad-d974a22c4620]
+description = "division -> performs integer division"
+
+[a5df3219-29b4-4d2f-b427-81f82f42a3f1]
+description = "division -> errors if dividing by zero"
+
+[1d5bb6b3-6749-4e02-8a79-b5d4d334cb8a]
+description = "division -> errors if there is nothing on the stack"
+
+[d5547f43-c2ff-4d5c-9cb0-2a4f6684c20d]
+description = "division -> errors if there is only one value on the stack"
+
+[f224f3e0-b6b6-4864-81de-9769ecefa03f]
+description = "division -> more than two values on the stack"
+
+[ee28d729-6692-4a30-b9be-0d830c52a68c]
+description = "combined arithmetic -> addition and subtraction"
+
+[40b197da-fa4b-4aca-a50b-f000d19422c1]
+description = "combined arithmetic -> multiplication and division"
+
+[f749b540-53aa-458e-87ec-a70797eddbcb]
+description = "combined arithmetic -> multiplication and addition"
+
+[c8e5a4c2-f9bf-4805-9a35-3c3314e4989a]
+description = "combined arithmetic -> addition and multiplication"
+
+[c5758235-6eef-4bf6-ab62-c878e50b9957]
+description = "dup -> copies a value on the stack"
+
+[f6889006-5a40-41e7-beb3-43b09e5a22f4]
+description = "dup -> copies the top value on the stack"
+
+[40b7569c-8401-4bd4-a30d-9adf70d11bc4]
+description = "dup -> errors if there is nothing on the stack"
+
+[1971da68-1df2-4569-927a-72bf5bb7263c]
+description = "drop -> removes the top value on the stack if it is the only one"
+
+[8929d9f2-4a78-4e0f-90ad-be1a0f313fd9]
+description = "drop -> removes the top value on the stack if it is not the only one"
+
+[6dd31873-6dd7-4cb8-9e90-7daa33ba045c]
+description = "drop -> errors if there is nothing on the stack"
+
+[3ee68e62-f98a-4cce-9e6c-8aae6c65a4e3]
+description = "swap -> swaps the top two values on the stack if they are the only ones"
+
+[8ce869d5-a503-44e4-ab55-1da36816ff1c]
+description = "swap -> swaps the top two values on the stack if they are not the only ones"
+
+[74ba5b2a-b028-4759-9176-c5c0e7b2b154]
+description = "swap -> errors if there is nothing on the stack"
+
+[dd52e154-5d0d-4a5c-9e5d-73eb36052bc8]
+description = "swap -> errors if there is only one value on the stack"
+
+[a2654074-ba68-4f93-b014-6b12693a8b50]
+description = "over -> copies the second element if there are only two"
+
+[c5b51097-741a-4da7-8736-5c93fa856339]
+description = "over -> copies the second element if there are more than two"
+
+[6e1703a6-5963-4a03-abba-02e77e3181fd]
+description = "over -> errors if there is nothing on the stack"
+
+[ee574dc4-ef71-46f6-8c6a-b4af3a10c45f]
+description = "over -> errors if there is only one value on the stack"
+
+[ed45cbbf-4dbf-4901-825b-54b20dbee53b]
+description = "user-defined words -> can consist of built-in words"
+include = false
+
+[2726ea44-73e4-436b-bc2b-5ff0c6aa014b]
+description = "user-defined words -> execute in the right order"
+include = false
+
+[9e53c2d0-b8ef-4ad8-b2c9-a559b421eb33]
+description = "user-defined words -> can override other user-defined words"
+include = false
+
+[669db3f3-5bd6-4be0-83d1-618cd6e4984b]
+description = "user-defined words -> can override built-in words"
+include = false
+
+[588de2f0-c56e-4c68-be0b-0bb1e603c500]
+description = "user-defined words -> can override built-in operators"
+include = false
+
+[ac12aaaf-26c6-4a10-8b3c-1c958fa2914c]
+description = "user-defined words -> can use different words with the same name"
+include = false
+
+[53f82ef0-2750-4ccb-ac04-5d8c1aefabb1]
+description = "user-defined words -> can define word that uses word with the same name"
+include = false
+
+[35958cee-a976-4a0f-9378-f678518fa322]
+description = "user-defined words -> cannot redefine non-negative numbers"
+include = false
+
+[df5b2815-3843-4f55-b16c-c3ed507292a7]
+description = "user-defined words -> cannot redefine negative numbers"
+include = false
+
+[5180f261-89dd-491e-b230-62737e09806f]
+description = "user-defined words -> errors if executing a non-existent word"
+include = false
+
+[3c8bfef3-edbb-49c1-9993-21d4030043cb]
+description = "user-defined words -> only defines locally"
+include = false
+
+[7b83bb2e-b0e8-461f-ad3b-96ee2e111ed6]
+description = "case-insensitivity -> DUP is case-insensitive"
+
+[339ed30b-f5b4-47ff-ab1c-67591a9cd336]
+description = "case-insensitivity -> DROP is case-insensitive"
+
+[ee1af31e-1355-4b1b-bb95-f9d0b2961b87]
+description = "case-insensitivity -> SWAP is case-insensitive"
+
+[acdc3a49-14c8-4cc2-945d-11edee6408fa]
+description = "case-insensitivity -> OVER is case-insensitive"
+
+[5934454f-a24f-4efc-9fdd-5794e5f0c23c]
+description = "case-insensitivity -> user-defined words are case-insensitive"
+include = false
+
+[037d4299-195f-4be7-a46d-f07ca6280a06]
+description = "case-insensitivity -> definitions are case-insensitive"
+include = false

exercises/practice/forth/forth.ua

@@ -0,0 +1,3 @@
+# Evaluate Forth code
+# Stack ? Instructions
+Evaluate ← |1 ⊙(⍤"Please implement Evaluate" 0)

exercises/practice/forth/tests.ua

@@ -0,0 +1,109 @@
+~ "forth.ua" ~ Evaluate
+
+# Parsing and numbers - numbers just get pushed onto the stack
+⍤⤙≍ [1 2 3 4 5] Evaluate "1 2 3 4 5"
+
+# Parsing and numbers - pushes negative numbers onto the stack
+⍤⤙≍ [¯1 ¯2 ¯3 ¯4 ¯5] Evaluate "-1 -2 -3 -4 -5"
+
+# Addition - can add two numbers
+⍤⤙≍ [3] Evaluate "1 2 +"
+
+# Addition - errors if there is nothing on the stack
+⍤⤙≍ "empty stack" ⍣(Evaluate "+")
+
+# Addition - errors if there is only one value on the stack
+⍤⤙≍ "only one value on the stack" ⍣(Evaluate "1 +")
+
+# Subtraction - can subtract two numbers
+⍤⤙≍ [¯1] Evaluate "3 4 -"
+
+# Subtraction - errors if there is nothing on the stack
+⍤⤙≍ "empty stack" ⍣(Evaluate "-")
+
+# Subtraction - errors if there is only one value on the stack
+⍤⤙≍ "only one value on the stack" ⍣(Evaluate "1 -")
+
+# Multiplication - can multiply two numbers
+⍤⤙≍ [8] Evaluate "2 4 *"
+
+# Multiplication - errors if there is nothing on the stack
+⍤⤙≍ "empty stack" ⍣(Evaluate "*")
+
+# Multiplication - errors if there is only one value on the stack
+⍤⤙≍ "only one value on the stack" ⍣(Evaluate "1 *")
+
+# Division - can divide two numbers
+⍤⤙≍ [4] Evaluate "12 3 /"
+
+# Division - performs integer division
+⍤⤙≍ [2] Evaluate "8 3 /"
+
+# Division - errors if dividing by zero
+⍤⤙≍ "divide by zero" ⍣(Evaluate "4 0 /")
+
+# Division - errors if there is nothing on the stack
+⍤⤙≍ "empty stack" ⍣(Evaluate "/")
+
+# Division - errors if there is only one value on the stack
+⍤⤙≍ "only one value on the stack" ⍣(Evaluate "1 /")
+
+# Combined arithmetic - addition and subtraction
+⍤⤙≍ [¯1] Evaluate "1 2 + 4 -"
+
+# Combined arithmetic - multiplication and division
+⍤⤙≍ [2] Evaluate "2 4 * 3 /"
+
+# Dup - copies a value on the stack
+⍤⤙≍ [1 1] Evaluate "1 dup"
+
+# Dup - copies the top value on the stack
+⍤⤙≍ [1 2 2] Evaluate "1 2 dup"
+
+# Dup - errors if there is nothing on the stack
+⍤⤙≍ "empty stack" ⍣(Evaluate "dup")
+
+# Drop - removes the top value on the stack if it is the only one
+⍤⤙≍ [] Evaluate "1 drop"
+
+# Drop - removes the top value on the stack if it is not the only one
+⍤⤙≍ [1] Evaluate "1 2 drop"
+
+# Drop - errors if there is nothing on the stack
+⍤⤙≍ "empty stack" ⍣(Evaluate "drop")
+
+# Swap - swaps the top two values on the stack if they are the only ones
+⍤⤙≍ [2 1] Evaluate "1 2 swap"
+
+# Swap - swaps the top two values on the stack if they are not the only ones
+⍤⤙≍ [1 3 2] Evaluate "1 2 3 swap"
+
+# Swap - errors if there is nothing on the stack
+⍤⤙≍ "empty stack" ⍣(Evaluate "swap")
+
+# Swap - errors if there is only one value on the stack
+⍤⤙≍ "only one value on the stack" ⍣(Evaluate "1 swap")
+
+# Over - copies the second element if there are only two
+⍤⤙≍ [1 2 1] Evaluate "1 2 over"
+
+# Over - copies the second element if there are more than two
+⍤⤙≍ [1 2 3 2] Evaluate "1 2 3 over"
+
+# Over - errors if there is nothing on the stack
+⍤⤙≍ "empty stack" ⍣(Evaluate "over")
+
+# Over - errors if there is only one value on the stack
+⍤⤙≍ "only one value on the stack" ⍣(Evaluate "1 over")
+
+# Case-insensitivity - DUP is case-insensitive
+⍤⤙≍ [1 1 1 1] Evaluate "1 DUP Dup dup"
+
+# Case-insensitivity - DROP is case-insensitive
+⍤⤙≍ [1] Evaluate "1 2 3 4 DROP Drop drop"
+
+# Case-insensitivity - SWAP is case-insensitive
+⍤⤙≍ [2 3 4 1] Evaluate "1 2 SWAP 3 Swap 4 swap"
+
+# Case-insensitivity - OVER is case-insensitive
+⍤⤙≍ [1 2 1 2 1] Evaluate "1 2 OVER Over over"