added format specification in the manual

manual.typ

@@ -1,4 +1,6 @@
 #import "@preview/tidy:0.3.0"
+#import "@preview/codelst:2.0.1": sourcecode
+#import "@preview/showybox:2.0.1": showybox
 #import "src/lib.typ"
 #import "src/schema.typ"
 #import "docs/examples.typ"
@@ -26,13 +28,26 @@
   link(label(label-name))[#display-name]
 }
 
+#let note(it) = showybox(
+  title: "Note",
+  title-style: (
+    color: white,
+    weight: "bold"
+  ),
+  frame: (
+    title-color: blue.lighten(30%),
+    border-color: blue.darken(40%)
+  ),
+  it
+)
+
 #show link: set text(blue)
 
 = Introduction
 
 This package provides a way to make beautiful register diagrams using the CeTZ package. It can be used to document Assembly instructions or binary registers
 
-This is a port of the #link("https://git.kb28.ch/HEL/rivet")[homonymous Python script] for Typst. For more information on the schema format, please check out the original project's #link("https://git.kb28.ch/HEL/rivet/src/branch/main/format.md")[format.md]
+This is a port of the #link("https://git.kb28.ch/HEL/rivet")[homonymous Python script] for Typst.
 
 = Usage
 
@@ -43,6 +58,185 @@ Simply import `schema` from #link("src/lib.typ") and call `schema.load` to parse
 #schema.render(doc)
 ```]
 
+= Format
+
+This section describes the structure of a schema definition. The examples given use the JSON syntax. For examples in different formats, see #link("https://git.kb28.ch/HEL/rivet-typst/src/branch/main/gallery/test.yaml")[test.yaml], #link("https://git.kb28.ch/HEL/rivet-typst/src/branch/main/gallery/test.json")[test.json] and #link("https://git.kb28.ch/HEL/rivet-typst/src/branch/main/gallery/test.xml")[test.xml]. You can also directly define a schema using Typst dictionaries and arrays.
+
+Since the XML format is quite different from the other, you might find it helpful to look at the examples on GitHub to get familiar with it.
+
+== Main layout
+
+A schema contains a dictionary of structures. The must be at least one defined structure named "main".
+
+It can also optionnaly contain a "colors" dictionary. More details about this in #link(<format-colors>)[Colors]
+
+#sourcecode[```json
+{
+  "structures": {
+    "main": {
+      ...
+    },
+    "struct1": {
+      ...
+    },
+    "struct2": {
+      ...
+    },
+    ...
+  }
+}
+```]
+
+#pagebreak(weak: true)
+
+== Structure <format-structure>
+
+A structure has a given number of bits and one or multiple ranges. Each range of bits can have a name, a description and / or values with special meaning (see #link(<format-range>)[Range]). A range's structure can also depend on another range's value (see #link(<format-dependencies>)[Dependencies]).
+
+The range name (or key) defines the left- and rightmost bits (e.g. `7-4` goes from bit 7 down to bit 4). Bits are displayed in big-endian, i.e. the leftmost bit has the highest value.
+
+#sourcecode[```json
+"main": {
+  "bits": 8,
+  "ranges": {
+    "7-4": {
+      ...
+    },
+    "3-2": {
+      ...
+    },
+    "1": {
+      ...
+    },
+    "0": {
+      ...
+    }
+  }
+}
+```]
+
+== Range <format-range>
+
+A range represents a group of consecutive bits. It can have a name (displayed in the bit cells), a description (displayed under the structure) and / or values.
+
+For values depending on other ranges, see #link(<format-dependencies>)[Dependencies].
+
+#note[
+  In YAML, make sure to wrap values in quotes because some values can be interpreted as octal notation (e.g. 010 #sym.arrow.r 8)
+]
+
+#sourcecode[```json
+"3-2": {
+  "name": "op",
+  "description": "Logical operation",
+  "values": {
+    "00": "AND",
+    "01": "OR",
+    "10": "XOR",
+    "11": "NAND"
+  }
+}
+```]
+
+#pagebreak(weak: true)
+
+== Dependencies <format-dependencies>
+
+The structure of one range may depend on the value of another. To represent this situation, first indicate on the child range the range on which it depends.
+
+Then, in its values, indicate which structure to use. A description can also be added (displayed above the horizontal dependency arrow)
+
+#sourcecode[```json
+"7-4": {
+  ...
+  "depends-on": "0",
+  "values": {
+    "0": {
+      "description": "immediate value",
+      "structure": "immediateValue"
+    },
+    "1": {
+      "description": "value in register",
+      "structure": "registerValue"
+    }
+  }
+}
+```]
+
+Finally, add the sub-structures to the structure dictionary:
+
+#sourcecode[```json
+{
+  "structures": {
+    "main": {
+      ...
+    },
+    "immediateValue": {
+      "bits": 4,
+      ...
+    },
+    "registerValue": {
+      "bits": 4,
+      ...
+    },
+    ...
+  }
+}
+```]
+
+#pagebreak(weak: true)
+
+== Colors <format-colors>
+
+You may want to highlight some ranges to make your diagram more readable. For this, you can use colors. Colors may be defined in a separate dictionary, at the same level as the "structures" dictionary:
+
+#sourcecode[```json
+{
+  "structures": {
+    ...
+  },
+  "colors": {
+    ...
+  }
+}
+```]
+
+It can contain color definitions for any number of ranges. For each range, you may then define a dictionary mapping bit ranges to a particular color:
+
+#sourcecode[```json
+"colors": {
+  "main": {
+    "31-28": "#ABCDEF",
+    "27-20": "12,34,56"
+  },
+  "registerValue": {
+    "19-10": [12, 34, 56]
+  }
+}
+```]
+
+Valid color formats are:
+- hex string starting with `#`, e.g. `"#23fa78"`
+- array of three integers (only JSON, YAML and Typst), e.g. `[35, 250, 120]`
+- string of three comma-separated integers (useful for XML), e.g. `"35,250,120"`
+- a Typst color (only Typst), e.g. `colors.green` or `rgb(35, 250, 120)`
+
+#note[
+  The XML format implements colors a bit differently. Instead of having a "colors" dictionary, color definitions are directly put on the same level as structure definitions. For this, you can use a `color` node with the attributes "structure", "color", "start" and "end", like so:
+  #sourcecode[```xml
+  <schema>
+    <structure id="main" bits="8">
+      ...
+    </structure>
+    ...
+    <color structure="main" color="#FF0000" start="4" end="7" />
+    <color structure="main" color="255,0,0" start="0" end="3" />
+  </schema>
+  ```]
+]
+
+#pagebreak(weak: true)
+
 = Config presets
 
 Aside from the default config, some example presets are also provided: