Adapt the assembler to the changes on the parser

As of 184c39579227 ("Re-work the parser from scratch") the parser has a
proper AST, and the assembler has to traverse it accordingly.

Moreover, the assembler has been stripped from a lot of unneeded memory
allocations and it's overall more keen on using mere references when
possible.

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

1 files changed, 93 insertions, 5 deletions

diff --git a/lib/xixanta/src/errors.rs b/lib/xixanta/src/errors.rs
index 6c99f57..d5444df 100644
--- a/lib/xixanta/src/errors.rs
+++ b/lib/xixanta/src/errors.rs
@@ -1,23 +1,35 @@
 use std::fmt;
 
-// TODO: global error
-// TODO: more errors, the `parse` thing is a hack!
+#[derive(Debug, Clone, PartialEq)]
+pub enum Error {
+    Parse(ParseError),
+    Context(ContextError),
+    Eval(EvalError),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Error::Parse(parse_error) => write!(f, "{}", parse_error),
+            Error::Context(context_error) => write!(f, "{}", context_error),
+            Error::Eval(eval_error) => write!(f, "{}", eval_error),
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq)]
 pub struct ParseError {
     pub line: usize,
     pub message: String,
-    pub parse: bool,
 }
 
 impl std::error::Error for ParseError {}
 
 impl From<std::io::Error> for ParseError {
     fn from(err: std::io::Error) -> Self {
-        // TODO
         ParseError {
             line: 0,
             message: err.to_string(),
-            parse: true,
         }
     }
 }
@@ -27,3 +39,79 @@ impl fmt::Display for ParseError {
         write!(f, "parser (line {}): {}.", self.line + 1, self.message)
     }
 }
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum ContextErrorReason {
+    Redefinition,
+    UnknownVariable,
+    BadScope,
+    Other,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct ContextError {
+    pub line: usize,
+    pub reason: ContextErrorReason,
+    pub message: String,
+}
+
+impl std::error::Error for ContextError {}
+
+// TODO: needed?
+impl From<std::io::Error> for ContextError {
+    fn from(err: std::io::Error) -> Self {
+        ContextError {
+            line: 0,
+            reason: ContextErrorReason::Other,
+            message: err.to_string(),
+        }
+    }
+}
+
+impl fmt::Display for ContextError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "Context error (line {}): {}.",
+            self.line + 1,
+            self.message
+        )
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct EvalError {
+    pub line: usize,
+    pub message: String,
+}
+
+impl std::error::Error for EvalError {}
+
+impl From<std::io::Error> for EvalError {
+    fn from(err: std::io::Error) -> Self {
+        EvalError {
+            line: 0,
+            message: err.to_string(),
+        }
+    }
+}
+
+impl From<ContextError> for EvalError {
+    fn from(err: ContextError) -> Self {
+        EvalError {
+            line: err.line,
+            message: err.message,
+        }
+    }
+}
+
+impl fmt::Display for EvalError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "Evaluation error (line {}): {}.",
+            self.line + 1,
+            self.message
+        )
+    }
+}