initial commit + basic sequences

src/diagram.typ

@@ -0,0 +1,51 @@
+#import "renderer.typ": render
+
+#let _seq(p1, p2, comment: none, style: auto) = {
+  return ((
+    type: "seq",
+    p1: p1,
+    p2: p2,
+    comment: comment,
+    style: style
+  ),)
+}
+
+#let _par(name, display-name: auto, start-at: 0) = {
+  return ((
+    type: "par",
+    name: name,
+    display-name: if display-name == auto {name} else {display-name},
+    start-at: start-at
+  ),)
+}
+
+#let _par-exists(participants, name) = {
+  for p in participants {
+    if name == p.name {
+      return true
+    }
+  }
+  return false
+}
+
+#let diagram(elements) = {
+  let participants = ()
+  for elmt in elements {
+    if elmt.type == "par" {
+      participants.push(elmt)
+    } else if elmt.type == "seq" {
+      if not _par-exists(participants, elmt.p1) {
+        participants.push(_par(elmt.p1).first())
+      }
+      if not _par-exists(participants, elmt.p2) {
+        participants.push(_par(elmt.p2).first())
+      }
+    }
+  }
+
+  render(participants, elements)
+}
+
+#let from-plantuml(code) = {
+  let code = code.text
+}