From 9103aa7a266a56f0b628baa7d32aee5d723acf6d Mon Sep 17 00:00:00 2001
From: Sebastian Schmidt <isibboi@gmail.com>
Date: Tue, 13 Jul 2021 13:55:22 +0300
Subject: [PATCH] Make more functions const.

---
 src/operator/mod.rs | 14 +++++---------
 src/token/mod.rs    |  8 +++-----
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/src/operator/mod.rs b/src/operator/mod.rs
index 0ae3794..3ebf4a1 100644
--- a/src/operator/mod.rs
+++ b/src/operator/mod.rs
@@ -102,8 +102,7 @@ impl Operator {
 
     /// Returns the precedence of the operator.
     /// A high precedence means that the operator has priority to be deeper in the tree.
-    // Make this a const fn once #57563 is resolved
-    pub(crate) fn precedence(&self) -> i32 {
+    pub(crate) const fn precedence(&self) -> i32 {
         use crate::operator::Operator::*;
         match self {
             RootNode => 200,
@@ -133,28 +132,25 @@ impl Operator {
     /// Returns true if chains of operators with the same precedence as this one should be evaluated left-to-right,
     /// and false if they should be evaluated right-to-left.
     /// Left-to-right chaining has priority if operators with different order but same precedence are chained.
-    // Make this a const fn once #57563 is resolved
-    pub(crate) fn is_left_to_right(&self) -> bool {
+    pub(crate) const fn is_left_to_right(&self) -> bool {
         use crate::operator::Operator::*;
         !matches!(self, Assign | FunctionIdentifier { identifier: _ })
     }
 
     /// Returns true if chains of this operator should be flattened into one operator with many arguments.
-    // Make this a const fn once #57563 is resolved
-    pub(crate) fn is_sequence(&self) -> bool {
+    pub(crate) const fn is_sequence(&self) -> bool {
         use crate::operator::Operator::*;
         matches!(self, Tuple | Chain)
     }
 
     /// True if this operator is a leaf, meaning it accepts no arguments.
-    // Make this a const fn once #57563 is resolved
+    // Make this a const fn as soon as whatever is missing gets stable (issue #57563)
     pub(crate) fn is_leaf(&self) -> bool {
         self.max_argument_amount() == Some(0)
     }
 
     /// Returns the maximum amount of arguments required by this operator.
-    // Make this a const fn once #57563 is resolved
-    pub(crate) fn max_argument_amount(&self) -> Option<usize> {
+    pub(crate) const fn max_argument_amount(&self) -> Option<usize> {
         use crate::operator::Operator::*;
         match self {
             Add | Sub | Mul | Div | Mod | Exp | Eq | Neq | Gt | Lt | Geq | Leq | And | Or
diff --git a/src/token/mod.rs b/src/token/mod.rs
index 56b05f1..0ae8c85 100644
--- a/src/token/mod.rs
+++ b/src/token/mod.rs
@@ -88,7 +88,7 @@ pub enum PartialToken {
     VerticalBar,
 }
 
-// Make this a const fn as soon as match gets stable (issue #57563)
+// Make this a const fn as soon as is_whitespace and to_string get stable (issue #57563)
 fn char_to_partial_token(c: char) -> PartialToken {
     match c {
         '+' => PartialToken::Plus,
@@ -122,8 +122,7 @@ fn char_to_partial_token(c: char) -> PartialToken {
 }
 
 impl Token {
-    // Make this a const fn as soon as match gets stable (issue #57563)
-    pub(crate) fn is_leftsided_value(&self) -> bool {
+    pub(crate) const fn is_leftsided_value(&self) -> bool {
         match self {
             Token::Plus => false,
             Token::Minus => false,
@@ -166,8 +165,7 @@ impl Token {
         }
     }
 
-    // Make this a const fn as soon as match gets stable (issue #57563)
-    pub(crate) fn is_rightsided_value(&self) -> bool {
+    pub(crate) const fn is_rightsided_value(&self) -> bool {
         match self {
             Token::Plus => false,
             Token::Minus => false,