diff --git a/rsconcept/frontend/package.json b/rsconcept/frontend/package.json
index 815bf50f..dd1e2f40 100644
--- a/rsconcept/frontend/package.json
+++ b/rsconcept/frontend/package.json
@@ -4,7 +4,7 @@
   "version": "1.0.0",
   "type": "module",
   "scripts": {
-    "prepare": "lezer-generator src/components/RSInput/rslang.grammar -o src/components/RSInput/rslangparser.ts",
+    "prepare": "lezer-generator src/components/RSInput/rslang/rslang.grammar -o src/components/RSInput/rslang/parser.ts",
     "test": "jest",
     "dev": "vite",
     "build": "tsc && vite build",
diff --git a/rsconcept/frontend/src/components/RSInput/highlight.ts b/rsconcept/frontend/src/components/RSInput/highlight.ts
deleted file mode 100644
index 27746107..00000000
--- a/rsconcept/frontend/src/components/RSInput/highlight.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-import {styleTags, tags} from '@lezer/highlight';
-
-export const highlighting = styleTags({
-  Identifier: tags.name,
-  Number: tags.number,
-  String: tags.string
-});
\ No newline at end of file
diff --git a/rsconcept/frontend/src/components/RSInput/RSInput.tsx b/rsconcept/frontend/src/components/RSInput/index.tsx
similarity index 72%
rename from rsconcept/frontend/src/components/RSInput/RSInput.tsx
rename to rsconcept/frontend/src/components/RSInput/index.tsx
index 88701847..240c3994 100644
--- a/rsconcept/frontend/src/components/RSInput/RSInput.tsx
+++ b/rsconcept/frontend/src/components/RSInput/index.tsx
@@ -1,11 +1,13 @@
 import { bracketMatching } from '@codemirror/language';
 import { Extension } from '@codemirror/state';
+import { tags as t } from '@lezer/highlight';
 import { createTheme } from '@uiw/codemirror-themes';
 import CodeMirror, { BasicSetupOptions, ReactCodeMirrorProps, ReactCodeMirrorRef } from '@uiw/react-codemirror';
 import { EditorView } from 'codemirror';
 import { Ref, useMemo } from 'react';
 
 import { useConceptTheme } from '../../context/ThemeContext';
+import { RSLanguage } from './rslang';
 
 const editorSetup: BasicSetupOptions = {
   highlightSpecialChars: true,
@@ -37,6 +39,7 @@ const editorSetup: BasicSetupOptions = {
 
 const editorExtensions = [
   EditorView.lineWrapping,
+  RSLanguage,
   bracketMatching()
 ];
 
@@ -62,15 +65,16 @@ function RSInput({
       fontFamily: 'inherit',
       background: editable ? '#ffffff' : '#f0f2f7',
       foreground: '#000000',
-      selection: '#036dd626',
-      selectionMatch: '#036dd626',
+      selection: '#aacef2',
       caret: '#5d00ff',
     },
     styles: [
-      // { tag: t.comment, color: '#787b8099' },
-      // { tag: t.variableName, color: '#0080ff' },
-      // { tag: [t.string, t.special(t.brace)], color: '#5c6166' },
-      // { tag: t.definition(t.typeName), color: '#5c6166' },
+      { tag: t.name, class: 'text-[#b266ff]' }, // GlobalID
+      { tag: t.variableName, class: 'text-[#24821a]' }, // LocalID
+      { tag: t.propertyName, class: '' }, // Radical
+      { tag: t.keyword, class: 'text-[#001aff]' }, // keywords
+      { tag: t.controlKeyword, class: 'font-semibold'}, // R | I | D
+      { tag: t.unit, class: 'text-[0.75rem]' }, // indicies
     ]
   }), [editable]);
   
@@ -81,20 +85,21 @@ function RSInput({
       fontFamily: 'inherit',
       background: editable ? '#070b12' : '#374151',
       foreground: '#e4e4e7',
-      selection: '#ffae00b0',
-      selectionMatch: '#ffae00b0',
+      selection: '#8c6000',
       caret: '#ffaa00'
     },
     styles: [
-      // { tag: t.comment, color: '#787b8099' },
-      // { tag: t.variableName, color: '#0080ff' },
-      // { tag: [t.string, t.special(t.brace)], color: '#5c6166' },
-      // { tag: t.definition(t.typeName), color: '#5c6166' },
+      { tag: t.name, class: 'text-[#dfbfff]' }, // GlobalID
+      { tag: t.variableName, class: 'text-[#69bf60]' }, // LocalID
+      { tag: t.propertyName, class: '' }, // Radical
+      { tag: t.keyword, class: 'text-[#808dff]' }, // keywords
+      { tag: t.controlKeyword, class: 'font-semibold'}, // R | I | D
+      { tag: t.unit, class: 'text-[0.75rem]' }, // indicies
     ]
   }), [editable]);
 
   return (
-    <div className={`w-full h-[${height}] ${cursor}`}>
+    <div className={`w-full h-[${height}] ${cursor} text-lg`}>
     <CodeMirror
       ref={innerref}
       basicSetup={editorSetup}
diff --git a/rsconcept/frontend/src/components/RSInput/rslang.grammar b/rsconcept/frontend/src/components/RSInput/rslang.grammar
deleted file mode 100644
index aa478c22..00000000
--- a/rsconcept/frontend/src/components/RSInput/rslang.grammar
+++ /dev/null
@@ -1,20 +0,0 @@
-@top Program { expression* }
-
-@skip { space }
-
-expression {
-  Identifier |
-  String |
-  Application { "(" expression* ")" }
-}
-
-@tokens {
-  space { @whitespace+ }
-  Identifier { $[a-zA-Z_\-0-9]+ }
-  String { '"' (!["\\] | "\\" _)* '"' }
-  "(" ")"
-}
-
-@detectDelim
-
-@external propSource highlighting from "./highlight.ts"
\ No newline at end of file
diff --git a/rsconcept/frontend/src/components/RSInput/rslang/highlight.ts b/rsconcept/frontend/src/components/RSInput/rslang/highlight.ts
new file mode 100644
index 00000000..5a9eba86
--- /dev/null
+++ b/rsconcept/frontend/src/components/RSInput/rslang/highlight.ts
@@ -0,0 +1,14 @@
+import {styleTags, tags} from '@lezer/highlight';
+
+export const highlighting = styleTags({
+  Index: tags.unit,
+  ComplexIndex: tags.unit,
+  Integer: tags.literal,
+
+  Radical: tags.propertyName,
+  Global: tags.name,
+  Local: tags.variableName,
+
+  TextFunction: tags.keyword,
+  ConstructPrefix: tags.controlKeyword
+});
\ No newline at end of file
diff --git a/rsconcept/frontend/src/components/RSInput/rslang/index.ts b/rsconcept/frontend/src/components/RSInput/rslang/index.ts
new file mode 100644
index 00000000..29aa8c2a
--- /dev/null
+++ b/rsconcept/frontend/src/components/RSInput/rslang/index.ts
@@ -0,0 +1,8 @@
+import {LRLanguage} from "@codemirror/language"
+
+import { parser } from './parser';
+
+export const RSLanguage = LRLanguage.define({
+  parser: parser,
+  languageData: {}
+});
\ No newline at end of file
diff --git a/rsconcept/frontend/src/components/RSInput/rslang/parser.terms.ts b/rsconcept/frontend/src/components/RSInput/rslang/parser.terms.ts
new file mode 100644
index 00000000..915682e3
--- /dev/null
+++ b/rsconcept/frontend/src/components/RSInput/rslang/parser.terms.ts
@@ -0,0 +1,11 @@
+// This file was generated by lezer-generator. You probably shouldn't edit it.
+export const
+  Expression = 1,
+  TextFunction = 2,
+  ComplexIndex = 3,
+  ConstructPrefix = 4,
+  Integer = 5,
+  Global = 6,
+  Radical = 7,
+  Local = 8,
+  Index = 9
diff --git a/rsconcept/frontend/src/components/RSInput/rslang/parser.ts b/rsconcept/frontend/src/components/RSInput/rslang/parser.ts
new file mode 100644
index 00000000..d5a0dc71
--- /dev/null
+++ b/rsconcept/frontend/src/components/RSInput/rslang/parser.ts
@@ -0,0 +1,18 @@
+// This file was generated by lezer-generator. You probably shouldn't edit it.
+import {LRParser} from "@lezer/lr"
+import {highlighting} from "./highlight.ts"
+export const parser = LRParser.deserialize({
+  version: 14,
+  states: "!^QVQPOOO}QPO'#C^OOQO'#C^'#C^O!SQQO'#CdOOQO'#Cj'#CjOOQO'#Cf'#CfQVQPOOOOQO,58x,58xOOQO,59O,59OOOQO-E6d-E6d",
+  stateData: "#a~O]OS~OSSOTSOUSOVSO_PO`POaPObQOcQOdQOeQOfRO~ORVO~OXWOSWXTWXUWXVWXZWX_WX`WXaWXbWXcWXdWXeWXfWX~Oa_T]UVSbcde`bf~",
+  goto: "n_PP`PPPPP`PdPPPjTSOUQUORXUTTOU",
+  nodeNames: "⚠ Expression TextFunction ComplexIndex ConstructPrefix Integer Global Radical Local Index",
+  maxTerm: 22,
+  propSources: [highlighting],
+  skippedNodes: [0],
+  repeatNodeCount: 1,
+  tokenData: ".p~RqX^#Ypq#Y!Q!R%m!R![%u!c!d&b!e!f&b!f!g&p!h!i&x!k!l'W!r!s']!t!u'k!u!v&b!v!w&b!z!{&b#R#S'{#T#U'{#U#V(W#V#W)j#W#X*y#X#d'{#d#e-P#e#f'{#f#g-o#g#o'{#y#z#Y$f$g#Y5i6S'{#BY#BZ#Y$IS$I_#Y$I|$JO#Y$JT$JU#Y$KV$KW#Y&FU&FV#Y~#_Z]~X^#Ypq#Y!Q![$Q#y#z#Y$f$g#Y#BY#BZ#Y$IS$I_#Y$I|$JO#Y$JT$JU#Y$KV$KW#Y&FU&FV#Y~$VZT~X^$xpq$x!Q![$Q#y#z$x$f$g$x#BY#BZ$x$IS$I_$x$I|$JO$x$JT$JU$x$KV$KW$x&FU&FV$x~$}YT~X^$xpq$x#y#z$x$f$g$x#BY#BZ$x$IS$I_$x$I|$JO$x$JT$JU$x$KV$KW$x&FU&FV$xQ%rPXQ!Q![%mR%|QRPXQ|}&S!Q![%mP&VP!R![&YP&_PRP|}&S~&eP!Q![&h~&mPU~!Q![&h~&uPS~!Q![&h~&{Q!Q![&h#]#^'R~'WOa~~']OS~~'`Q!Q![&h#f#g'f~'kO_~~'pPS~!Q!['s~'xPV~!Q!['s~(QQf~#T#o'{5i6S'{~(]Sf~#T#c'{#c#d(i#d#o'{5i6S'{~(nSf~#T#c'{#c#d(z#d#o'{5i6S'{~)PSf~#T#`'{#`#a)]#a#o'{5i6S'{~)dQc~f~#T#o'{5i6S'{~)oRf~#T#U)x#U#o'{5i6S'{~)}Sf~#T#f'{#f#g*Z#g#o'{5i6S'{~*`Sf~#T#W'{#W#X*l#X#o'{5i6S'{~*sQb~f~#T#o'{5i6S'{~+OSf~#T#X'{#X#Y+[#Y#o'{5i6S'{~+aSf~#T#U'{#U#V+m#V#o'{5i6S'{~+rSf~#T#c'{#c#d,O#d#o'{5i6S'{~,TSf~#T#c'{#c#d,a#d#o'{5i6S'{~,fSf~#T#`'{#`#a,r#a#o'{5i6S'{~,yQd~f~#T#o'{5i6S'{~-USf~#T#f'{#f#g-b#g#o'{5i6S'{~-iQ`~f~#T#o'{5i6S'{~-tSf~#T#X'{#X#Y.Q#Y#o'{5i6S'{~.VSf~#T#W'{#W#X.c#X#o'{5i6S'{~.jQe~f~#T#o'{5i6S'{",
+  tokenizers: [0, 1],
+  topRules: {"Expression":[0,1]},
+  tokenPrec: 94
+})
diff --git a/rsconcept/frontend/src/components/RSInput/rslang/rslang.grammar b/rsconcept/frontend/src/components/RSInput/rslang/rslang.grammar
new file mode 100644
index 00000000..d53c3412
--- /dev/null
+++ b/rsconcept/frontend/src/components/RSInput/rslang/rslang.grammar
@@ -0,0 +1,61 @@
+@top Expression { token* }
+
+@skip { space }
+
+@tokens {
+  space { @whitespace+ }
+  Index { $[0-9]+ }
+  ComplexIndex { $[1-9](","$[1-9])* }
+  Integer { space$[0-9]+space? }
+
+  bigPr { "Pr" }
+  smallPr { "pr" }
+  filter { "Fi" }
+  card { "card" }
+  bool { "bool" }
+  debool { "debool" }
+  red { "red" }
+
+  ConstructPrefix { "D" | "R" | "I"  }
+
+  Global { $[XCSDAPTF]$[0-9]+ }
+  Radical { "R"$[0-9]+ }
+  local { $[_a-zα-ω]$[a-zα-ω]* }
+
+  "(" ")"
+  "[" "]"
+  "{" "}"
+  
+  @precedence { filter bigPr Global Radical ConstructPrefix }
+  @precedence { card bool debool red smallPr local }
+  @precedence { Integer space }
+}
+
+TextFunction {
+  bigPr ComplexIndex |
+  smallPr ComplexIndex |
+  filter ComplexIndex |
+  card | bool | debool | red
+}
+
+Local { local Index? }
+
+token {
+  TextFunction |
+  ConstructPrefix |
+  Integer |
+  Global |
+  Radical |
+  Local
+}
+
+@detectDelim
+
+@external propSource highlighting from "./highlight.ts"
+
+//@asciiLetter matches $[a-zA-Z]
+//@asciiLowercase matches $[a-z]
+//@asciiUppercase is equivalent to $[A-Z]
+//@digit matches $[0-9]
+//@whitespace matches any character the Unicode standard defines as whitespace.
+//@eof matches the end of the input
\ No newline at end of file
diff --git a/rsconcept/frontend/src/components/RSInput/rslangparser.terms.ts b/rsconcept/frontend/src/components/RSInput/rslangparser.terms.ts
deleted file mode 100644
index 2e607541..00000000
--- a/rsconcept/frontend/src/components/RSInput/rslangparser.terms.ts
+++ /dev/null
@@ -1,5 +0,0 @@
-// This file was generated by lezer-generator. You probably shouldn't edit it.
-export const
-  Program = 1,
-  Identifier = 2,
-  String = 3
diff --git a/rsconcept/frontend/src/components/RSInput/rslangparser.ts b/rsconcept/frontend/src/components/RSInput/rslangparser.ts
deleted file mode 100644
index 4f74c8be..00000000
--- a/rsconcept/frontend/src/components/RSInput/rslangparser.ts
+++ /dev/null
@@ -1,22 +0,0 @@
-// This file was generated by lezer-generator. You probably shouldn't edit it.
-import {LRParser} from "@lezer/lr"
-import {highlighting} from "./highlight.ts"
-export const parser = LRParser.deserialize({
-  version: 14,
-  states: "!WQVQPOOObQPO'#CbOOQO'#Cg'#CgOOQO'#Cc'#CcQVQPOOOOQO,58|,58|OpQPO,58|OOQO-E6a-E6aOOQO1G.h1G.h",
-  stateData: "!O~OYOS~OQQORQOTPO~OQQORQOSTOTPO~OQQORQOSWOTPO~O",
-  goto: "s[PPPPPP]cPPPmXQOPSUQSOQUPTVSUXROPSU",
-  nodeNames: "⚠ Program Identifier String ) ( Application",
-  maxTerm: 11,
-  nodeProps: [
-    ["openedBy", 4,"("],
-    ["closedBy", 5,")"]
-  ],
-  propSources: [highlighting],
-  skippedNodes: [0],
-  repeatNodeCount: 1,
-  tokenData: "%[~RbX^!Zpq!Zrs#Oxy$lyz$q}!O$v!Q![$v!c!}$v#R#S$v#T#o$v#y#z!Z$f$g!Z#BY#BZ!Z$IS$I_!Z$I|$JO!Z$JT$JU!Z$KV$KW!Z&FU&FV!Z~!`YY~X^!Zpq!Z#y#z!Z$f$g!Z#BY#BZ!Z$IS$I_!Z$I|$JO!Z$JT$JU!Z$KV$KW!Z&FU&FV!Z~#RVOr#Ors#hs#O#O#O#P#m#P;'S#O;'S;=`$f<%lO#O~#mOR~~#pRO;'S#O;'S;=`#y;=`O#O~#|WOr#Ors#hs#O#O#O#P#m#P;'S#O;'S;=`$f;=`<%l#O<%lO#O~$iP;=`<%l#O~$qOT~~$vOS~~${TQ~}!O$v!Q![$v!c!}$v#R#S$v#T#o$v",
-  tokenizers: [0],
-  topRules: {"Program":[0,1]},
-  tokenPrec: 0
-})
diff --git a/rsconcept/frontend/src/index.css b/rsconcept/frontend/src/index.css
index 54ac9339..2217f5b9 100644
--- a/rsconcept/frontend/src/index.css
+++ b/rsconcept/frontend/src/index.css
@@ -19,11 +19,17 @@
 }
 
 .cm-editor {
-  @apply border shadow rounded clr-border px-2
+  @apply border shadow rounded clr-border px-1
 }
 .cm-editor.cm-focused {
   @apply border shadow rounded outline-2 outline
 }
+.cm-matchingBracket {
+  @apply font-semibold
+}
+.cm-nonmatchingBracket {
+  @apply font-bold text-red-500
+}
 
 @layer components {
   h1 {
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression.tsx
index 3fa6df1d..ce154ffb 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression.tsx
@@ -4,7 +4,7 @@ import { useCallback, useLayoutEffect, useMemo, useRef, useState } from 'react';
 import Button from '../../components/Common/Button';
 import Label from '../../components/Common/Label';
 import { Loader } from '../../components/Common/Loader';
-import RSInput from '../../components/RSInput/RSInput';
+import RSInput from '../../components/RSInput';
 import { getSymbolSubstitute, TextWrapper } from '../../components/RSInput/textEditing';
 import { useRSForm } from '../../context/RSFormContext';
 import useCheckExpression from '../../hooks/useCheckExpression';