Indexing vectors by ⟦⟧

cli/src/repl.rs

@@ -108,7 +108,7 @@ impl Highlighter for LineHighlighter {
             r"(?x)
             (?P<op>([+\-/*%^!×÷⋅]|if|otherwise|load|exit|clear|help)) |
             (?P<radix>0[box][a-zA-Z0-9]+) |
-            (?P<identifier>[^!-@\s_|^⌊⌋⌈⌉\[\]\{\}≠≥≤⁰¹²³⁴⁵⁶⁷⁸⁹⁺⁻⁼⁽⁾₀₁₂₃₄₅₆₇₈₉₊₋₌₍₎]+(_\d+)?)",
+            (?P<identifier>[^!-@\s_|^⌊⌋⌈⌉\[\]\{\}⟦⟧≠≥≤⁰¹²³⁴⁵⁶⁷⁸⁹⁺⁻⁼⁽⁾₀₁₂₃₄₅₆₇₈₉₊₋₌₍₎]+(_\d+)?)",
         )
         .unwrap();
 
@@ -154,6 +154,7 @@ lazy_static! {
         m.insert("sqrt", "√");
         m.insert("tau", "τ");
         m.insert("(", "()");
+        m.insert("[[", "⟦⟧");
         m.insert("!=", "≠");
         m.insert(">=", "≥");
         m.insert("<=", "≤");
@@ -212,7 +213,7 @@ impl Completer for RLHelper {
     fn update(&self, line: &mut rustyline::line_buffer::LineBuffer, start: usize, elected: &str) {
         line.backspace(line.pos() - start);
         line.insert_str(line.pos(), elected);
-        line.move_forward(if elected.ends_with(")") {
+        line.move_forward(if elected.ends_with(")") || elected.ends_with("⟧") {
             elected.chars().count() - 1
         } else {
             elected.chars().count()

kalk/src/lexer.rs

@@ -37,7 +37,9 @@ pub enum TokenKind {
     OpenParenthesis,
     ClosedParenthesis,
     OpenBracket,
+    OpenDoubleBracket,
     ClosedBracket,
+    ClosedDoubleBracket,
     OpenBrace,
     ClosedBrace,
     Comma,
@@ -134,6 +136,8 @@ impl<'a> Lexer<'a> {
             ')' => build(TokenKind::ClosedParenthesis, "", span),
             '[' => build(TokenKind::OpenBracket, "", span),
             ']' => build(TokenKind::ClosedBracket, "", span),
+            '⟦' => build(TokenKind::OpenDoubleBracket, "", span),
+            '⟧' => build(TokenKind::ClosedDoubleBracket, "", span),
             '{' => build(TokenKind::OpenBrace, "", span),
             '}' => build(TokenKind::ClosedBrace, "", span),
             '!' => build(TokenKind::Exclamation, "", span),
@@ -167,6 +171,14 @@ impl<'a> Lexer<'a> {
                 self.advance();
                 return build(TokenKind::Power, "", span);
             }
+            (TokenKind::OpenBracket, Some('[')) => {
+                self.advance();
+                return build(TokenKind::OpenDoubleBracket, "", span);
+            }
+            (TokenKind::ClosedBracket, Some(']')) => {
+                self.advance();
+                return build(TokenKind::ClosedDoubleBracket, "", span);
+            }
             (TokenKind::Exclamation, Some('=')) => {
                 self.advance();
                 return build(TokenKind::NotEquals, "", span);
@@ -370,7 +382,7 @@ fn is_valid_identifier(c: Option<&char>) -> bool {
         match c {
             '+' | '-' | '/' | '*' | '%' | '^' | '!' | '(' | ')' | '=' | '.' | ',' | ';' | '|'
             | '⌊' | '⌋' | '⌈' | '⌉' | '[' | ']' | '{' | '}' | 'π' | '√' | 'τ' | 'ϕ' | 'Γ' | '<'
-            | '>' | '≠' | '≥' | '≤' | '×' | '÷' | '⋅' | '\n' => false,
+            | '>' | '≠' | '≥' | '≤' | '×' | '÷' | '⋅' | '⟦' | '⟧' | '\n' => false,
             _ => !c.is_digit(10) || is_superscript(c) || is_subscript(c),
         }
     } else {

kalk/src/parser.rs

@@ -549,7 +549,7 @@ fn parse_unary(context: &mut Context) -> Result<Expr, CalcError> {
 }
 
 fn parse_exponent(context: &mut Context) -> Result<Expr, CalcError> {
-    let left = parse_factorial(context)?;
+    let left = parse_indexer(context)?;
 
     if match_token(context, TokenKind::Power) {
         let op = advance(context).kind;
@@ -560,6 +560,19 @@ fn parse_exponent(context: &mut Context) -> Result<Expr, CalcError> {
     Ok(left)
 }
 
+fn parse_indexer(context: &mut Context) -> Result<Expr, CalcError> {
+    let left = parse_factorial(context)?;
+
+    if match_token(context, TokenKind::OpenDoubleBracket) {
+        advance(context);
+        let right = Box::new(parse_expr(context)?);
+        consume(context, TokenKind::ClosedDoubleBracket)?;
+        return Ok(Expr::Indexer(Box::new(left), right));
+    }
+
+    Ok(left)
+}
+
 fn parse_factorial(context: &mut Context) -> Result<Expr, CalcError> {
     let expr = parse_primary(context)?;
 

web/src/KalkCalculator.svelte

@@ -282,18 +282,27 @@
         let result = input;
         let offset = 0;
         result = result.replace(
-            /(?<radix>0[box][a-zA-Z0-9]+)|(?<comparison>(!=|[<>]=?))|(?<html>[<>&]|(\n\s*\}?|\s+))|(?<op>([+\-/*%^!≈×÷⋅]|if|otherwise)|(?<identifier>[^!-@\s_|^⌊⌋⌈⌉≈\[\]\{\}≠≥≤⁰¹²³⁴⁵⁶⁷⁸⁹⁺⁻⁼⁽⁾₀₁₂₃₄₅₆₇₈₉₊₋₌₍₎]+(_\d+)?)\(?)/g,
+            /(?<brackets>\[\[)|(?<radix>0[box][a-zA-Z0-9]+)|(?<comparison>(!=|[<>]=?))|(?<html>[<>&]|(\n\s*\}?|\s+))|(?<op>([+\-/*%^!≈×÷⋅]|if|otherwise)|(?<identifier>[^!-@\s_|^⌊⌋⌈⌉≈\[\]\{\}⟦⟧≠≥≤⁰¹²³⁴⁵⁶⁷⁸⁹⁺⁻⁼⁽⁾₀₁₂₃₄₅₆₇₈₉₊₋₌₍₎]+(_\d+)?)\(?)/g,
             (
                 substring,
+                brackets,
                 _radix,
-                _,
-                comparison,
                 _2,
-                html,
+                comparison,
                 _3,
+                html,
+                _4,
                 op,
                 identifier
             ) => {
+                if (brackets) {
+                    if (substring == "[[") {
+                        offset -= 1;
+
+                        return "⟦⟧";
+                    }
+                }
+
                 if (comparison) {
                     if (substring == "<=") return "≤";
                     if (substring == ">=") return "≥";