1 files changed, 189 insertions, 0 deletions
diff --git a/src/makefile/macro.rs b/src/makefile/macro.rs
new file mode 100644
index 0000000..139903f
--- /dev/null
+++ b/src/makefile/macro.rs
@@ -0,0 +1,189 @@
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::env;
+use std::fmt;
+use std::rc::{Rc, Weak};
+
+use regex::Regex;
+
+use super::functions;
+use super::token::{Token, TokenString};
+
+#[derive(Debug, Clone)]
+pub(crate) enum MacroSource {
+    File,
+    CommandLineOrMakeflags,
+    Environment,
+    Builtin,
+}
+
+pub(crate) trait LookupInternal: for<'a> Fn(&'a str) -> String {}
+
+impl<F: for<'a> Fn(&'a str) -> String> LookupInternal for F {}
+
+fn lookup_fail(_: &str) -> String {
+    panic!("internal variables not available!");
+}
+
+#[derive(Clone)]
+pub(crate) struct MacroSet {
+    data: HashMap<String, (MacroSource, TokenString)>,
+    lookup_internal: RefCell<Weak<dyn LookupInternal>>,
+}
+
+impl MacroSet {
+    pub(crate) fn new() -> Self {
+        let lookup_fail: Rc<dyn LookupInternal> = Rc::new(lookup_fail);
+        Self {
+            data: HashMap::new(),
+            lookup_internal: RefCell::new(Rc::downgrade(&lookup_fail)),
+        }
+    }
+
+    pub(crate) fn lookup(&self, lookup: Weak<dyn LookupInternal>) {
+        self.lookup_internal.replace(lookup);
+    }
+
+    pub(crate) fn add_builtins(&mut self) {
+        for (k, v) in builtins() {
+            self.data.insert(k.into(), (MacroSource::Builtin, v));
+        }
+    }
+
+    pub(crate) fn add_env(&mut self) {
+        for (k, v) in env::vars() {
+            if k != "MAKEFLAGS" && k != "SHELL" {
+                self.data
+                    .insert(k, (MacroSource::Environment, TokenString::text(v)));
+            }
+        }
+    }
+
+    pub(crate) fn set(&mut self, name: String, source: MacroSource, text: TokenString) {
+        self.data.insert(name, (source, text));
+    }
+
+    pub(crate) fn is_defined(&self, name: &str) -> bool {
+        self.data.contains_key(name)
+    }
+
+    pub(crate) fn get(&self, name: &str) -> Option<&(MacroSource, TokenString)> {
+        self.data.get(name)
+    }
+
+    // `remove` is fine, but I think for "remove-and-return" `pop` is better
+    pub(crate) fn pop(&mut self, name: &str) -> Option<(MacroSource, TokenString)> {
+        self.data.remove(name)
+    }
+
+    pub(crate) fn expand(&self, text: &TokenString) -> String {
+        let mut result = String::new();
+        for token in text.tokens() {
+            match token {
+                Token::Text(t) => result.push_str(t),
+                Token::MacroExpansion { name, replacement } => {
+                    let internal_macro_names = &['@', '?', '<', '*'][..];
+                    let internal_macro_suffices = &['D', 'F'][..];
+                    let just_internal = name.len() == 1 && name.starts_with(internal_macro_names);
+                    let suffixed_internal = name.len() == 2
+                        && name.starts_with(internal_macro_names)
+                        && name.ends_with(internal_macro_suffices);
+                    let macro_value = if just_internal || suffixed_internal {
+                        let lookup_internal = self.lookup_internal.borrow();
+                        let lookup_internal = match lookup_internal.upgrade() {
+                            Some(f) => f,
+                            None => Rc::new(lookup_fail),
+                        };
+                        lookup_internal(name)
+                    } else {
+                        self.data
+                            .get(name)
+                            .map_or_else(String::new, |(_, macro_value)| self.expand(macro_value))
+                    };
+                    let macro_value = match replacement {
+                        Some((subst1, subst2)) => {
+                            let subst1 = self.expand(subst1);
+                            let subst1_suffix = regex::escape(&subst1);
+                            let subst1_suffix =
+                                Regex::new(&format!(r"{}\b", subst1_suffix)).unwrap();
+                            let subst2 = self.expand(subst2);
+                            subst1_suffix.replace_all(&macro_value, subst2).to_string()
+                        }
+                        None => macro_value,
+                    };
+                    result.push_str(&macro_value);
+                }
+                Token::FunctionCall { name, args } => {
+                    result.push_str(&functions::call(name, args, &self));
+                }
+            }
+        }
+        result
+    }
+}
+
+impl fmt::Debug for MacroSet {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:?}", &self.data)
+    }
+}
+
+impl fmt::Display for MacroSet {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let pieces = self
+            .data
+            .iter()
+            .map(|(k, (_, v))| format!("{}={}", k, v))
+            .collect::<Vec<_>>();
+        write!(f, "{}", pieces.join("\n"))
+    }
+}
+
+fn builtins() -> Vec<(&'static str, TokenString)> {
+    // Fuck it, might as well.
+    macro_rules! handle {
+        ($value:ident) => {
+            stringify!($value)
+        };
+        ($value:literal) => {
+            $value
+        };
+    }
+    macro_rules! make {
+        ($($name:ident=$value:tt)+) => {vec![$(
+            (stringify!($name), handle!($value).parse().unwrap())
+        ),+]};
+    }
+
+    make![
+        MAKE=makers
+        AR=ar
+        YACC=yacc
+        YFLAGS=""
+        LEX=lex
+        LFLAGS=""
+        LDFLAGS=""
+
+        AS=as
+        CC=cc
+        CXX="g++"
+        CPP="$(CC) -E"
+        FC=f77
+        PC=pc
+        CO=co
+        GET=get
+        LINT=lint
+        MAKEINFO=makeinfo
+        TEX=tex
+        TEXI2DVI=texi2dvi
+        WEAVE=weave
+        CWEAVE=cweave
+        TANGLE=tangle
+        CTANGLE=ctangle
+        RM="rm -f"
+
+        ARFLAGS="rv"
+        CFLAGS=""
+        FFLAGS=""
+    ]
+}