init

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -0,0 +1,69 @@
+# ---> CMake
+CMakeLists.txt.user
+CMakeCache.txt
+CMakeFiles
+CMakeScripts
+Testing
+Makefile
+cmake_install.cmake
+install_manifest.txt
+compile_commands.json
+CTestTestfile.cmake
+_deps
+CMakeUserPresets.json
+
+# ---> C
+# Prerequisites
+*.d
+
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Linker output
+*.ilk
+*.map
+*.exp
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
+
+# Kernel Module Compile Results
+*.mod*
+*.cmd
+.tmp_versions/
+modules.order
+Module.symvers
+Mkfile.old
+dkms.conf
+
+build

CMakeLists.txt

@@ -0,0 +1,4 @@
+cmake_minimum_required(VERSION 3.10)
+project(PS1)
+
+add_executable(ps1 src/driver.c)

LICENSE

@@ -0,0 +1,18 @@
+MIT License
+
+Copyright (c) 2026 frero-uni
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and 
+associated documentation files (the "Software"), to deal in the Software without restriction, including 
+without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
+copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the 
+following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial 
+portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT 
+LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO 
+EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 
+USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

@@ -0,0 +1,3 @@
+# TDT4205
+
+compiler construction

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1769461804,
+        "narHash": "sha256-msG8SU5WsBUfVVa/9RPLaymvi5bI8edTavbIq3vRlhI=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "bfc1b8a4574108ceef22f02bafcf6611380c100d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,23 @@
+{
+  description = "DevShell with flex, bison, gdb, cmake";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+  outputs =
+    { self, nixpkgs }:
+    let
+      system = "x86_64-linux";
+      pkgs = nixpkgs.legacyPackages.${system};
+    in
+    {
+      devShells.${system}.default = pkgs.mkShell {
+        buildInputs = with pkgs; [
+          flex
+          bison
+          gdb
+          cmake
+          libgcc
+        ];
+      };
+    };
+}

src/driver.c

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+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "table.c"
+
+static_assert(START >= 0 && START < NSTATES, "START must be a valid state");
+static_assert(ACCEPT >= 0 && ACCEPT < NSTATES, "ACCEPT must be a valid state");
+static_assert(ERROR >= 0 && ERROR < NSTATES, "ERROR must be a valid state");
+
+// This program takes in lines from stdin and validates them line by line.
+// If a line is valid, it is ignored.
+// Otherwise, it is printed in full,
+// followed by a line indicating at which character the error occurs.
+int main() {
+
+    // Fill the table first. This function does no input processing only table creation.
+    fillTable();
+    printf("Table filled!\n");
+
+    // Lines may not be more than 512 lines long
+    char line[512];
+    int lineNum = 0;
+
+    // For each line in input
+    while (fgets(line, sizeof(line), stdin)) {
+        lineNum++;
+
+        int state = START;
+        int pos = 0;
+        bool fatalError = false;
+        while (true) {
+            unsigned char c = line[pos];
+
+            // If the line ended without a newline, patch it in
+            if (c == '\0')
+                c = '\n';
+
+            // Use the symbol to go to the next state
+            state = table[state][c];
+
+            // Uncomment this for debugging:
+            /* printf("State %i got c=%c\n", state, c); */
+
+            if (state < 0 || state >= NSTATES) {
+                printf("fatal error: DFS entered an invalid state: %d\n", state);
+                fatalError = true;
+            }
+            else if (state == ACCEPT) {
+                // Make sure statement is accepted at new line
+                if (c == '\n') {
+                    printf("line %4d: accepted: %.*s\n", lineNum, pos, line);
+
+                    // Break inner loop
+                    break;
+                }
+
+                printf("fatal error: ACCEPT state reached before end of line:\n");
+                fatalError = true;
+            }
+            else if (c == '\n' && state != ERROR) {
+                printf("fatal error: Line ended without reaching either ACCEPT or ERROR state: %d\n", state);
+                fatalError = true;
+            }
+
+            // Provide the position we were at in the string when the DFS reached the ERROR state,
+            // or when a fatal error occured. The latter can only happen if the DFS is broken.
+            if (state == ERROR || fatalError) {
+                printf("line %4d: error: %s", lineNum, line);
+                printf("~~~~~~~~~~~~~~~~~~");
+                for(int i = 0; i < pos; i++)
+                    putc('~', stdout);
+                printf("^\n");
+                break;
+            }
+
+            pos++;
+        }
+
+        // Fatal errors means there is something wrong with the DFS table. Stop processing lines!
+        if (fatalError) {
+            return 1; // return code 1 means error
+        }
+    }
+
+    return 0;
+}

src/table.c

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+// The number of states in your table
+#define NSTATES 14
+
+// The starting state, at the beginning of each line
+#define START 0
+
+// The state to go to after a valid line
+// All lines end with the newline character '\n'
+#define ACCEPT 12
+
+// The state to jump to as soon as a line is invalid
+#define ERROR 13
+
+int table[NSTATES][256];
+
+void fillTable() {
+
+    // Make all states lead to ERROR by default
+    for (int i = 0; i < NSTATES; i++) {
+        for (int c = 0; c < 256; c++) {
+            table[i][c] = ERROR;
+        }
+    }
+
+    // Skip whitespace
+    table[START][' '] = START;
+
+    // If we reach a newline, and are not in the middle of a statement, accept
+    table[START]['\n'] = ACCEPT;
+
+    // Accept the statement "go"
+    table[START]['g'] = 1;
+    table[1]['o'] = 2;
+    table[2]['\n'] = ACCEPT;
+
+
+    // TODO Expand the table to pass (and fail) the described syntax
+    // table[...][...] = ...
+
+}

testing/expected/0-go.txt

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+Table filled!
+line    1: accepted: go
+line    2: error: apple
+~~~~~~~~~~~~~~~~~~^
+line    3: accepted: go
+line    4: accepted: 
+line    5: error: banana
+~~~~~~~~~~~~~~~~~~^
+line    6: accepted: go
+line    7: error: orange
+~~~~~~~~~~~~~~~~~~^

testing/expected/1-spaces.txt

@@ -0,0 +1,9 @@
+Table filled!
+line    1: accepted: go
+line    2: accepted: 
+line    3: accepted: go go
+line    4: error: go gogo
+~~~~~~~~~~~~~~~~~~~~~~~^
+line    5: accepted:  go go go  go go go 
+line    6: error: gogo gogo
+~~~~~~~~~~~~~~~~~~~~^

testing/expected/2-dxdy.txt

@@ -0,0 +1,21 @@
+Table filled!
+line    1: accepted: dx=2
+line    2: accepted: dy=3
+line    3: accepted: dx=9 
+line    4: accepted: dx=55
+line    5: accepted: dy=09
+line    6: accepted: dx=5 dx=1 go
+line    7: error: da=1
+~~~~~~~~~~~~~~~~~~~^
+line    8: error: indy=1
+~~~~~~~~~~~~~~~~~~^
+line    9: accepted: dx=999
+line   10: accepted: dy=-10
+line   11: error: dx=--5
+~~~~~~~~~~~~~~~~~~~~~~^
+line   12: error: dx=-
+~~~~~~~~~~~~~~~~~~~~~~^
+line   13: error: dy=
+~~~~~~~~~~~~~~~~~~~~~^
+line   14: accepted: dx=-0 dy=55 go dx=197 dy=-2
+line   15: accepted: dx=20     dy=20 

testing/expected/3-labels.txt

@@ -0,0 +1,16 @@
+Table filled!
+line    1: accepted: 8: go
+line    2: accepted:     10:    dx=1
+line    3: accepted: 5:go dx=2
+line    4: accepted: 2:
+line    5: error: -11: go go
+~~~~~~~~~~~~~~~~~~^
+line    6: accepted: 100: go dx=5
+line    7: error: apple: go
+~~~~~~~~~~~~~~~~~~^
+line    8: error: go 4:
+~~~~~~~~~~~~~~~~~~~~~^
+line    9: error: 22: 22: go
+~~~~~~~~~~~~~~~~~~~~~~^
+line   10: error: : go
+~~~~~~~~~~~~~~~~~~^

testing/expected/4-comments.txt

@@ -0,0 +1,14 @@
+Table filled!
+line    1: accepted: // This file contains tests
+line    2: accepted:    //Spacesbeforecommentshouldnotmatter
+line    3: accepted: go go go // This should be accepted
+line    4: accepted: 10: dx=10 dy=-5 go // This should also be accepted
+line    5: error: dx=-1 dy=5 go /* This should fail! */
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
+line    6: accepted: go go // dx=-4.2 should be accepted
+line    7: accepted: //
+line    8: accepted: go// Comments can be right next to statements
+line    9: accepted: dx=5// Here as well
+line   10: accepted: 7://Labels too!
+line   11: error: go / We need two slashes
+~~~~~~~~~~~~~~~~~~~~~~^

testing/expected/5-mixed_ok.txt

@@ -0,0 +1,9 @@
+Table filled!
+line    1: accepted: go   go dx=1 go
+line    2: accepted:  go// OK
+line    3: accepted: 9: dx=-1 //
+line    4: accepted: 10: //
+line    5: accepted:  11://
+line    6: accepted: dy=-9     // Not dy=--9
+line    7: accepted: 00: dx=-0001 go
+line    8: accepted: 94124543535: dx=94124543535 go dy=-111 go // End

testing/expected/6-mixed_err.txt

@@ -0,0 +1,21 @@
+Table filled!
+line    1: error: dx= // Comment
+~~~~~~~~~~~~~~~~~~~~~^
+line    2: error: go go goooo
+~~~~~~~~~~~~~~~~~~~~~~~~~~^
+line    3: error: dy=11dx=11
+~~~~~~~~~~~~~~~~~~~~~~~^
+line    4: error: -5: go
+~~~~~~~~~~~~~~~~~~^
+line    5: error: : // Empty label?
+~~~~~~~~~~~~~~~~~~^
+line    6: error: 5:4:
+~~~~~~~~~~~~~~~~~~~~^
+line    7: error: go / Comment
+~~~~~~~~~~~~~~~~~~~~~~^
+line    8: error: 8: dy=42 dx=4.2
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
+line    9: error: I beheld the wretch—the miserable monster whom I had created
+~~~~~~~~~~~~~~~~~~^
+line   10: error: apple pie
+~~~~~~~~~~~~~~~~~~^

testing/test.py

@@ -0,0 +1,87 @@
+import difflib
+import pathlib
+import os
+import subprocess
+import sys
+
+
+def main():
+    ps1_root_dir = pathlib.Path(__file__).parent.parent.resolve()
+
+    build_dir = ps1_root_dir / "build"
+
+    print("Building and compiling...")
+    try:
+        subprocess.run(["cmake", str(ps1_root_dir), "-B", str(build_dir)], check=True)
+        subprocess.run(["cmake", "--build", str(build_dir)], check=True)
+    except subprocess.CalledProcessError as e:
+        print(f"An error occurred while running CMake: {e}", file=sys.stderr)
+        sys.exit(1)
+    print("Build complete")
+
+    testing_dir = ps1_root_dir / "testing"
+    tests_dir = testing_dir / "tests"
+    outputs_dir = testing_dir / "expected"
+
+    executable = build_dir / "ps1"
+
+    sorted_test_files : list[pathlib.Path] = []
+
+    for test_file in tests_dir.glob("*.txt"):
+        sorted_test_files.append(test_file)
+    
+    sorted_test_files.sort(key= lambda p : p.name)
+
+    passed = 0
+    for test_file in sorted_test_files:
+        name = test_file.name
+        print(f"Testing {name}... ", end="")
+        output_file = outputs_dir / name
+
+        if not output_file.exists():
+            print("")
+            print(f"Error: Could not find {str(output_file)}", file=sys.stderr)
+            sys.exit(1)
+
+        try:
+            result : list[str] = []
+            with test_file.open("r") as test_input:
+                result_str : str = subprocess.run(
+                    [executable], 
+                    stdin=test_input, 
+                    stdout=subprocess.PIPE, 
+                    stderr=subprocess.PIPE,
+                    text=True,  # Output must be text
+                    check=True
+                ).stdout
+
+                result = result_str.splitlines()
+            
+            expected : list[str] = []
+            with output_file.open("r") as expected_output:
+                expected = expected_output.read().splitlines()
+            
+            diff_list : list[str] = []
+            for diff in difflib.unified_diff(result, expected, fromfile='your output', tofile='expected_output', lineterm='', n=3):
+                diff_list.append(diff)
+
+            if not diff_list:
+                # List is empty; no diffs
+                passed += 1
+                print("OK")
+                continue
+
+            # If at least one diff, print
+            print("MISMATCH")
+            for diff in diff_list:
+                print(diff)
+        
+        except subprocess.CalledProcessError as e:
+            print("")
+            print(f"Error: Test {name} failed to execute: {e}", file=sys.stderr)
+    
+    print(f"{passed}/{len(sorted_test_files)} tests passed")
+
+
+if __name__ == "__main__":
+    main()

testing/tests/0-go.txt

@@ -0,0 +1,7 @@
+go
+apple
+go
+
+banana
+go
+orange

testing/tests/1-spaces.txt

@@ -0,0 +1,6 @@
+go
+
+go go
+go gogo
+ go go go  go go go 
+gogo gogo

testing/tests/2-dxdy.txt

@@ -0,0 +1,15 @@
+dx=2
+dy=3
+dx=9 
+dx=55
+dy=09
+dx=5 dx=1 go
+da=1
+indy=1
+dx=999
+dy=-10
+dx=--5
+dx=-
+dy=
+dx=-0 dy=55 go dx=197 dy=-2
+dx=20     dy=20 

testing/tests/3-labels.txt

@@ -0,0 +1,10 @@
+8: go
+    10:    dx=1
+5:go dx=2
+2:
+-11: go go
+100: go dx=5
+apple: go
+go 4:
+22: 22: go
+: go

testing/tests/4-comments.txt

@@ -0,0 +1,11 @@
+// This file contains tests
+   //Spacesbeforecommentshouldnotmatter
+go go go // This should be accepted
+10: dx=10 dy=-5 go // This should also be accepted
+dx=-1 dy=5 go /* This should fail! */
+go go // dx=-4.2 should be accepted
+//
+go// Comments can be right next to statements
+dx=5// Here as well
+7://Labels too!
+go / We need two slashes

testing/tests/5-mixed_ok.txt

@@ -0,0 +1,8 @@
+go   go dx=1 go
+ go// OK
+9: dx=-1 //
+10: //
+ 11://
+dy=-9     // Not dy=--9
+00: dx=-0001 go
+94124543535: dx=94124543535 go dy=-111 go // End

testing/tests/6-mixed_err.txt

@@ -0,0 +1,10 @@
+dx= // Comment
+go go goooo
+dy=11dx=11
+-5: go
+: // Empty label?
+5:4:
+go / Comment
+8: dy=42 dx=4.2
+I beheld the wretch—the miserable monster whom I had created
+apple pie