diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..762d1bd
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,9 @@
+.idea/
+.vscode/
+
+target/
+
+Cargo.lock
+
+*.pdb
+**/*.rs.bk
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..c816dc1
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,24 @@
+[package]
+name = "pmp"
+description = "PHP Macro Pre-processor (PMP) written in Rust."
+
+version = "0.1.0-alpha"
+edition = "2024"
+
+[dependencies]
+clap = { version = "^4", features = ["derive"] }
+
+rayon = "^1"
+
+once_cell = "^1"
+
+mago-syntax = "^1.13"
+mago-interner = "^1.0.0-alpha"
+mago-source = "^1.0.0-alpha"
+mago-span = "^1.13"
+mago-names = "^1.13"
+mago-project = "^0.26"
+mago-semantics = "^1.13"
+
+regex = "^1"
+walkdir = "^2"
diff --git a/src/cli/flags.rs b/src/cli/flags.rs
new file mode 100644
index 0000000..a7d5e2c
--- /dev/null
+++ b/src/cli/flags.rs
@@ -0,0 +1,49 @@
+use std::{
+    ffi::OsStr,
+    path::PathBuf
+};
+use clap::{
+    Parser,
+    ValueHint::FilePath,
+};
+
+use crate::util::fs;
+
+#[derive(Parser, Debug)]
+#[command(name = "pmp", about, version)]
+pub struct Args {
+    #[arg(long, value_hint = FilePath, value_parser = fs::path_exists, help = "Path to PHP binary")]
+    php: Option<PathBuf>,
+
+    #[arg(long, short = 'd', hide = true)]
+    debug: bool,
+    #[arg(long, short = 'v', help = "Verbose output")]
+    verbose: bool,
+    #[arg(long, short = 'n', help = "Dry run, does not modify files or cache")]
+    dry_run: bool,
+
+    #[arg(long, short = 'e', value_hint = FilePath, value_parser = fs::path_exists, default_values_os = [OsStr::new(".gitignore"), OsStr::new("vendor/")], help = "Exclude files from pre-processing, e.g. vendor/")]
+    exclude: Vec<PathBuf>,
+    #[arg(long, short = 'c', value_hint = FilePath, value_parser = fs::valid_possible_path, default_value_os = OsStr::new(".cache"), help = "Cache directory location")]
+    cache_dir: Option<PathBuf>,
+    #[arg(long, short = 'o', value_hint = FilePath, value_parser = fs::valid_possible_path, default_value_os = OsStr::new("."), help = "Output directory location")]
+    output_dir: Option<PathBuf>,
+    #[arg(long, short = 'i', conflicts_with = "dry_run", help = "Invalidate cache and re-process all files")]
+    invalidate_cache: bool,
+
+    #[arg(value_hint = FilePath, value_parser = fs::path_exists, default_value_os = OsStr::new("."), help = "Directory to recursively scan and pre-process")]
+    directory: Option<PathBuf>,
+    #[arg(last = true)]
+    passthrough: Vec<String>,
+}
+
+// todo: ignore .gitignore marked content per default
+// todo: diff output with verbose and ofc trace for warnings/errors
+// todo: cache with file hashes and system last edited timestamp
+
+impl Args
+{
+    pub fn parse() -> Self {
+        <Self as Parser>::parse()
+    }
+}
diff --git a/src/cli/mod.rs b/src/cli/mod.rs
new file mode 100644
index 0000000..741db5a
--- /dev/null
+++ b/src/cli/mod.rs
@@ -0,0 +1,3 @@
+mod flags;
+
+pub use flags::Args;
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..714f64a
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,2 @@
+pub mod cli;
+pub mod util;
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..fcbf818
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,8 @@
+use pmp::{ cli::Args };
+
+fn main()
+{
+    let args = Args::parse();
+
+    println!("{:#?}", args);
+}
diff --git a/src/util/fs.rs b/src/util/fs.rs
new file mode 100644
index 0000000..29a2fd2
--- /dev/null
+++ b/src/util/fs.rs
@@ -0,0 +1,27 @@
+use regex::Regex;
+use std::path::PathBuf;
+use once_cell::sync::Lazy;
+
+static PATH_REGEX: Lazy<Regex> = Lazy::new(|| {
+    Regex::new(r"^[+-]?(\d+(\.\d*)?|\.\d+)([eE][+-]?\d+)?$").unwrap()
+});
+
+pub fn path_exists(s: &str) -> Result<PathBuf, String> {
+    let p = PathBuf::from(s);
+    p.exists().then_some(p).ok_or("path does not exist".to_string())
+}
+
+pub fn valid_possible_path(s: &str) -> Result<PathBuf, String>
+{
+    let lower = s.to_ascii_lowercase();
+
+    if lower == "true" || lower == "false" {
+        return Err("boolean literal is not allowed".into());
+    }
+
+    if PATH_REGEX.is_match(s) {
+        return Err("numeric literal is not allowed".into());
+    }
+
+    Ok(PathBuf::from(s))
+}
diff --git a/src/util/mod.rs b/src/util/mod.rs
new file mode 100644
index 0000000..d521fbd
--- /dev/null
+++ b/src/util/mod.rs
@@ -0,0 +1 @@
+pub mod fs;