From 3651b7fe18017544e8c8c83a37b160605ced5c4a Mon Sep 17 00:00:00 2001
From: Sander Hautvast <shautvast@gmail.com>
Date: Mon, 8 Mar 2021 17:38:58 +0100
Subject: [PATCH] support for arrays and a shorthand for vector

---
 README.md           |  6 +++++-
 src/js/functions.js |  2 +-
 src/js/index.js     | 10 ++++++++++
 src/js/parser.js    | 20 ++++++++++++++++++--
 src/js/scanner.js   |  3 +++
 5 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 2dd6f6c..bb638bd 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,11 @@ The repl has the following syntax (It's work in progress, new capabilities will
    ```a = vector(12, 1)```
   > &gt; vector@0{x0:0, y0: 2, x:12, y:1}
 * ```vector(1 2)``` works as well. The start is now the origin.
-  commas are not mandatory. I'm planning to add a more mathematical notation for vectors: ```[1 2]```
+  commas are not mandatory. 
+* This means spaces are meaningful. 
+  ```vector(-1 -1)``` != ```vector(-1-1)``` and the latter would mean ```vector(-2)``` which is not legal.
+* arrays: \[i<sub>0</sub> i<sub>1</sub> i<sub>2</sub> ... i<sub>n</sub>] or \[i<sub>0</sub>, i<sub>1</sub>, i<sub>2</sub>, ... i<sub>n</sub>] creates an array. 
+  * \[i<sub>0</sub> i<sub>1</sub>] is special: it is a shorthand for creating a vector. I'll have to think of another way to create an array of length 2...
   
 * properties
   * ```a = vector(12, 1)```
diff --git a/src/js/functions.js b/src/js/functions.js
index 79dee63..5af6def 100644
--- a/src/js/functions.js
+++ b/src/js/functions.js
@@ -65,7 +65,7 @@ const help = function () {
     }
 }
 
-const create_vector = function (x0, y0, x, y) { //rename to create_vector
+export const create_vector = function (x0, y0, x, y) { //rename to create_vector
     const vector = {
         id: index_sequence++,
         x0: x0,
diff --git a/src/js/index.js b/src/js/index.js
index 9b2c19a..88cde53 100644
--- a/src/js/index.js
+++ b/src/js/index.js
@@ -4,6 +4,7 @@ import {parse} from './parser';
 import {add_vector_arrow, add_vector_arrow_to_svg, update_vector_arrow} from "./svg_functions";
 import {
     addition,
+    create_vector,
     division,
     functions,
     label,
@@ -274,6 +275,15 @@ const visit = function (expr) {
         case 'reference': {
             return references[expr.name];
         }
+        case 'array': { //unsure this is what I want
+            let array = expr.elements.map(x => x.value);
+            if (array.length === 2) {
+                return create_vector(0, 0, array[0], array[1]);
+            } else {
+                return array;
+            }
+
+        }
     }
 }
 
diff --git a/src/js/parser.js b/src/js/parser.js
index 7d26670..efd8946 100644
--- a/src/js/parser.js
+++ b/src/js/parser.js
@@ -103,14 +103,13 @@ export const parse = function (tokens) {
                 } else {
                     throw {message: "Expect ')' after arguments."};
                 }
-                match([token_types.COMMA]);
+                match([token_types.COMMA, token_types.SPACE]);
             } while (!match([token_types.RIGHT_PAREN]));
         }
 
         return {type: 'call', name: callee, arguments: arguments_list};
     }
 
-
     function primary() {
         if (match([token_types.NUMERIC, token_types.STRING])) {
             return {type: 'literal', value: previous_token().value, value_type: previous_token().type};
@@ -147,6 +146,23 @@ export const parse = function (tokens) {
             };
             advance();
             return result;
+        } else if (match([token_types.LEFT_BRACKET])) {
+            let array = [];
+            if (!check(token_types.RIGHT_BRACKET, token_index)) {
+                let result;
+                do {
+                    result = expression();
+                    if (result) {
+                        array.push(result);
+                    } else {
+                        throw {message: "Expect ']' after array elements."};
+                    }
+                    match([token_types.COMMA, token_types.SPACE]);
+                } while (!match([token_types.RIGHT_BRACKET]));
+            }
+
+            return {type: 'array', elements: array};
+
         }
     }
 
diff --git a/src/js/scanner.js b/src/js/scanner.js
index 51055e7..d8f1b36 100644
--- a/src/js/scanner.js
+++ b/src/js/scanner.js
@@ -31,6 +31,8 @@ export const scan = function (command) {
                 return token_types.RIGHT_BRACKET;
             case ',':
                 return token_types.COMMA;
+            case ' ':
+                return token_types.SPACE;
             case '.':
                 return token_types.DOT;
             case '-':
@@ -192,6 +194,7 @@ export const token_types = {
     LEFT_BRACKET: {type: 'left_bracket'},
     RIGHT_BRACKET: {type: 'right_bracket'},
     COMMA: {type: 'comma'},
+    SPACE: {type: 'space'},
     DOT: {type: 'dot'},
     MINUS: {type: 'minus'},
     PLUS: {type: 'plus'},