From 3c21bf5a7b222ef8f13bdc226792a88046684528 Mon Sep 17 00:00:00 2001
From: "GASSER Thibaud (PRESTA EXT)" <thibaud.gasser@externe.e-i.com>
Date: Tue, 23 Jan 2024 14:51:55 +0100
Subject: [PATCH] [wip] brainfuck to c translator

---
 brainfuck-to-c-translator/solution.py | 106 ++++++++++++++++++++++++++
 brainfuck-to-c-translator/tests.py    |  32 ++++++++
 2 files changed, 138 insertions(+)
 create mode 100644 brainfuck-to-c-translator/solution.py
 create mode 100644 brainfuck-to-c-translator/tests.py

diff --git a/brainfuck-to-c-translator/solution.py b/brainfuck-to-c-translator/solution.py
new file mode 100644
index 0000000..64ce12c
--- /dev/null
+++ b/brainfuck-to-c-translator/solution.py
@@ -0,0 +1,106 @@
+# https://www.codewars.com/kata/58924f2ca8c628f21a0001a1/
+from enum import Enum, auto
+from dataclasses import dataclass
+
+
+class OpKind(Enum):
+    LEFT = '<'
+    RIGHT = '>'
+    INC = '+'
+    DEC = '-'
+    INPT = ','
+    OUTP = '.'
+    JMPZ = '['
+    JMPNZ = ']'
+
+
+@dataclass
+class Opcode:
+    kind: OpKind
+    operand: int = 1
+
+
+def stream_tokens(code) -> Opcode:
+    for c in code:
+        try:
+            yield Opcode(OpKind(c))
+        except ValueError:
+            continue
+
+
+def optimize(tokens):
+    new_tokens = opti_collapse_tokens(tokens)
+    if len(new_tokens) <= 1:
+        return new_tokens
+
+    
+    tokens = otpi_cancel_opposing(new_tokens)
+    while len(new_tokens := otpi_cancel_opposing(tokens)) != len(tokens):
+        tokens = new_tokens
+
+    return tokens
+
+
+def opti_collapse_tokens(tokens):
+    # collapse consecutive identical tokens
+    new_tokens = []
+    for next_token in tokens:
+        if new_tokens == []:  # init stack
+            new_tokens.append(next_token)
+            continue
+        current_token = new_tokens.pop()
+        if current_token.kind == next_token.kind and str(current_token.kind.value) in "<>+-":
+            current_token.operand += 1
+            new_tokens.append(current_token)
+        else:
+            new_tokens.append(current_token)
+            new_tokens.append(next_token)
+    return new_tokens
+
+
+def otpi_cancel_opposing(tokens):
+    # cancel opposing adjacent tokens
+    new_tokens = []
+    for next_token in tokens:
+        if new_tokens == []:  # init stack
+            new_tokens.append(next_token)
+            continue
+        current_token = new_tokens.pop()
+        if (current_token.kind.value + next_token.kind.value in ("+-", "-+", "<>", "><", "[]")
+            and current_token.operand == next_token.operand):
+            continue
+        else:
+            new_tokens.append(current_token)
+            new_tokens.append(next_token)
+    return new_tokens
+
+
+def generate_code(tokens):
+    out = []
+    nest = 0
+    # code generation
+    for token in tokens:
+        match token.kind:
+            case OpKind.LEFT: out.append(f"{' ' * nest * 2}p -= {token.operand};\n")
+            case OpKind.RIGHT: out.append(f"{' ' * nest * 2}p += {token.operand};\n")
+            case OpKind.INC: out.append(f"{' ' * nest * 2}*p += {token.operand};\n")
+            case OpKind.DEC: out.append(f"{' ' * nest * 2}*p -= {token.operand};\n")
+            case OpKind.INPT: out.append(f"{' ' * nest * 2}*p = getchar();\n")
+            case OpKind.OUTP: out.append(f"{' ' * nest * 2}putchar(*p);\n")
+            case OpKind.JMPZ: out.append(f"{' ' * nest * 2}" + "if (*p) do {\n");nest += 1
+            case OpKind.JMPNZ: nest -= 1;out.append(f"{' ' * nest * 2}" + "} while (*p);\n")
+        
+        if nest < 0:
+            return "Error!"
+            
+    if nest != 0:
+        return "Error!"
+
+    return "".join(out)
+
+
+def brainfuck_to_c(source_code):
+    s = stream_tokens(source_code)
+    tokens = optimize(s)
+    code = generate_code(tokens)
+    return code
diff --git a/brainfuck-to-c-translator/tests.py b/brainfuck-to-c-translator/tests.py
new file mode 100644
index 0000000..a83e5f0
--- /dev/null
+++ b/brainfuck-to-c-translator/tests.py
@@ -0,0 +1,32 @@
+import codewars_test as test
+from solution import brainfuck_to_c
+
+
+def testing(code, expected):
+    result = brainfuck_to_c(code)
+    test.assert_equals(result, expected)
+    
+test.describe("general tests")
+
+test.it("thib")
+testing("-+-+", "")
+testing("<>", "")
+#testing(">>><<<<", "<")
+
+test.it("basic")
+testing("+-", "")
+testing("++++", "*p += 4;\n")
+testing("----", "*p -= 4;\n")
+
+testing(">>>>", "p += 4;\n");
+testing("<<<<", "p -= 4;\n");
+    
+testing(".", "putchar(*p);\n");
+testing(",", "*p = getchar();\n");
+    
+testing("[[[]]", "Error!");
+    
+testing("[][]", "");
+    
+testing("[.]", "if (*p) do {\n  putchar(*p);\n} while (*p);\n");
+