Initial commit

A lot is missing and there is a long road ahead to make the assembler
even work.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/lib/xixanta/src/context.rs b/lib/xixanta/src/context.rs
new file mode 100644
index 0000000..62ec7e0
--- /dev/null
+++ b/lib/xixanta/src/context.rs
@@ -0,0 +1,66 @@
+use crate::instruction::PString;
+use std::collections::HashMap;
+
+const GLOBAL_CONTEXT: &str = "Global";
+
+#[derive(Debug)]
+pub struct Context {
+    stack: Vec<String>,
+    map: HashMap<String, HashMap<String, PString>>,
+}
+
+impl Default for Context {
+    fn default() -> Self {
+        Context::new()
+    }
+}
+
+impl Context {
+    pub fn new() -> Self {
+        Context {
+            stack: vec![],
+            map: HashMap::from([(String::from(GLOBAL_CONTEXT), HashMap::new())]),
+        }
+    }
+
+    pub fn reset(&mut self) {
+        self.stack = vec![];
+    }
+
+    pub fn find(&self, name: &str) -> Option<&HashMap<String, PString>> {
+        self.map.get(name)
+    }
+
+    pub fn current(&self) -> Option<&HashMap<String, PString>> {
+        match self.stack.last() {
+            Some(name) => self.map.get(name),
+            None => self.map.get(GLOBAL_CONTEXT),
+        }
+    }
+
+    pub fn current_mut(&mut self) -> Option<&mut HashMap<String, PString>> {
+        match self.stack.last() {
+            Some(name) => self.map.get_mut(name),
+            None => self.map.get_mut(GLOBAL_CONTEXT),
+        }
+    }
+
+    pub fn push(&mut self, identifier: &String) {
+        let name = match self.stack.last() {
+            Some(n) => n.to_owned() + &String::from("::") + identifier,
+            None => identifier.to_string(),
+        };
+
+        self.stack.push(name.clone());
+        self.map.entry(name).or_default();
+    }
+
+    pub fn pop(&mut self) -> bool {
+        if self.stack.is_empty() {
+            return false;
+        }
+
+        self.stack.truncate(self.stack.len() - 1);
+        true
+    }
+}