Add element structure

src/elements/group.rs

@@ -0,0 +1,59 @@
+use crate::elements::special::Expression;
+
+#[derive(Clone, Debug)]
+pub enum Group {
+    Parentheses(Parentheses),
+    Brackets(Brackets),
+    Braces(Braces),
+    Angles(Angles),
+    XGroup(XGroup),
+    Abs(Abs),
+    Floor(Floor),
+    Ceil(Ceil),
+    Norm(Norm),
+}
+
+#[derive(Clone, Debug)]
+pub struct Parentheses {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Brackets {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Braces {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Angles {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct XGroup {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Abs {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Floor {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Ceil {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Norm {
+    inner: Box<Expression>,
+}

src/elements/literal.rs

@@ -1,4 +1,4 @@
-use crate::tokens::{FontCommand, Greek};
+use crate::tokens::{Arrow, FontCommand, Function, Greek, Logical, Relation};
 
 #[derive(Clone, Debug)]
 pub enum Literal {
@@ -53,54 +53,15 @@ pub enum Literal {
     Rational,
     Real,
     Integer,
-    Eq,
-    Ne,
-    Lt,
-    Gt,
-    Le,
-    Ge,
-    Prec,
-    PrecEq,
-    Succ,
-    SuccEq,
-    In,
-    NotIn,
-    Subset,
-    SupSet,
-    SubSetEq,
-    SupSetEq,
-    Equiv,
-    Cong,
-    Approx,
-    PropTo,
-    And,
-    Or,
-    Not,
-    Implies,
-    If,
-    ForAll,
-    Exists,
-    Bot,
-    Top,
-    VDash,
-    Models,
-    UpArrow,
-    DownArrow,
-    RightArrow,
-    To,
-    RightArrowTail,
-    TwoHeadRightArrrow,
-    MapsTo,
-    LeftArrow,
-    LeftRightArrow,
-    BigRightArrow,
-    BigLeftArrow,
-    BigLeftRightArrow,
     Text(TextNode),
     Symbol(SymbolNode),
     Number(NumberNode),
     Greek(Greek),
     FontCommand(FontCommand),
+    Relation(Relation),
+    Function(Function),
+    Logical(Logical),
+    Arrow(Arrow),
 }
 
 #[derive(Clone, Debug)]

src/elements/mod.rs

@@ -1,5 +1,14 @@
+use crate::elements::group::Group;
+use crate::elements::literal::Literal;
+use crate::elements::special::Special;
+
+pub mod group;
 pub mod literal;
 pub mod special;
 
 #[derive(Debug, Clone)]
-pub enum Element {}
+pub enum Element {
+    Literal(Literal),
+    Special(Special),
+    Group(Group),
+}

src/elements/special.rs

@@ -1,6 +1,65 @@
 use crate::elements::Element;
 
 #[derive(Clone, Debug)]
-pub struct Root {
+pub struct Expression {
     children: Vec<Element>,
 }
+
+#[derive(Clone, Debug)]
+pub enum Special {
+    Sum(Sum),
+    Prod(Prod),
+    Frac(Frac),
+    Exp(Exp),
+    Sqrt(Sqrt),
+    Root(Root),
+    Integral(Integral),
+    OIntegral(OIntegral),
+}
+
+#[derive(Clone, Debug)]
+pub struct Sum {
+    top: Option<Expression>,
+    bottom: Option<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Prod {
+    top: Box<Expression>,
+    bottom: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Frac {
+    top: Box<Expression>,
+    bottom: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Exp {
+    base: Box<Element>,
+    exp: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Sqrt {
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Root {
+    base: Box<Expression>,
+    inner: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Integral {
+    top: Box<Expression>,
+    bottom: Box<Expression>,
+}
+
+#[derive(Clone, Debug)]
+pub struct OIntegral {
+    top: Box<Expression>,
+    bottom: Box<Expression>,
+}