From 9e32ff9e16bda64d82b7138a506a0833cfa9d761 Mon Sep 17 00:00:00 2001
From: Luna <git@l4.pm>
Date: Mon, 26 Aug 2019 15:19:31 -0300
Subject: [PATCH] parser: split into finishAssignment

---
 src/parser.zig | 69 ++++++++++++++++++++++++--------------------------
 1 file changed, 33 insertions(+), 36 deletions(-)

diff --git a/src/parser.zig b/src/parser.zig
index 0f3ffe6..d00465f 100644
--- a/src/parser.zig
+++ b/src/parser.zig
@@ -533,7 +533,7 @@ pub const Parser = struct {
         var expr: ?*Expr = null;
         var body: ast.Block = undefined;
 
-        // infinite loop
+        // 'loop {' = infinite loop
         if (self.check(.LeftBrace)) {
             body = try self.parseStmtBlock();
         } else {
@@ -570,7 +570,7 @@ pub const Parser = struct {
     }
 
     fn parseAssignment(self: *@This()) anyerror!*Expr {
-        // there can be two types coming out of this function:
+        // there can be two assignments coming out of this function:
         //  - a mutable/immutable variable declaration with :=
         //  - an assignment to a variable with =
 
@@ -578,53 +578,50 @@ pub const Parser = struct {
         // of this is an Expr, we wrap variable assignments in an Expr as well.
         var mutable: bool = false;
 
-        std.debug.warn("start assignment pass with cur={}\n", self.peek());
-
         if (self.check(.Mut)) {
             _ = try self.consumeSingle(.Mut);
             mutable = true;
         }
 
         var expr = try self.parseOr();
-        std.debug.warn("lvalue: {}, cur: {}\n", expr, self.peek());
-
-        var value: *Expr = undefined;
-
-        var op: Token = undefined;
 
         if (self.check(.ColonEqual) or self.check(.Equal)) {
-            op = self.peek();
-            _ = try self.nextToken();
-            value = try self.parseAssignment();
-
-            switch (expr.*) {
-                .Variable => {
-                    switch (op.ttype) {
-                        .ColonEqual => return try self.mkVarDecl(expr.Variable, value, mutable),
-                        .Equal => return try self.mkAssign(expr.Variable, value),
-                        else => unreachable,
-                    }
-                },
-
-                .Get => |get| {
-                    if (op.ttype == .ColonEqual) {
-                        self.doError("can not initialize struct field");
-                        return Result.CompileError;
-                    }
-
-                    return try self.mkSet(get.struc, get.name, value);
-                },
-
-                else => |expr_typ| {
-                    self.doError("Invalid assignment target {}", expr_typ);
-                    return Result.CompileError;
-                },
-            }
+            return try self.finishAssignment(expr, mutable);
         }
 
         return expr;
     }
 
+    fn finishAssignment(self: *@This(), expr: *Expr, mutable: bool) !*Expr {
+        var op = self.peek();
+        _ = try self.nextToken();
+        var value = try self.parseAssignment();
+
+        switch (expr.*) {
+            .Variable => {
+                switch (op.ttype) {
+                    .ColonEqual => return try self.mkVarDecl(expr.Variable, value, mutable),
+                    .Equal => return try self.mkAssign(expr.Variable, value),
+                    else => unreachable,
+                }
+            },
+
+            .Get => |get| {
+                if (op.ttype == .ColonEqual) {
+                    self.doError("can not initialize struct field");
+                    return Result.CompileError;
+                }
+
+                return try self.mkSet(get.struc, get.name, value);
+            },
+
+            else => |expr_typ| {
+                self.doError("Invalid assignment target {}", expr_typ);
+                return Result.CompileError;
+            },
+        }
+    }
+
     fn parseOr(self: *@This()) !*Expr {
         var expr = try self.parseAnd();