From e12525ca9d070d3c607fb8b6a93ab0db509081ee Mon Sep 17 00:00:00 2001
From: Juan Cruz Viotti <jv@jviotti.com>
Date: Tue, 18 Nov 2025 11:10:03 -0400
Subject: [PATCH] Add a `single-line-text` utility schema

Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>
---
 meta/schemas.json                    |  28 +--
 schemas/misc/single-line-text.json   |  15 ++
 test/misc/single-line-text.test.json | 341 +++++++++++++++++++++++++++
 3 files changed, 359 insertions(+), 25 deletions(-)
 create mode 100644 schemas/misc/single-line-text.json
 create mode 100644 test/misc/single-line-text.test.json

diff --git a/meta/schemas.json b/meta/schemas.json
index b4b6605c..b23fa2d6 100644
--- a/meta/schemas.json
+++ b/meta/schemas.json
@@ -5,35 +5,13 @@
   "properties": {
     "$id": false,
     "$comment": {
-      "$ref": "#/$defs/clean-prose"
+      "$ref": "../schemas/misc/single-line-text.json"
     },
     "title": {
-      "$ref": "#/$defs/clean-prose"
+      "$ref": "../schemas/misc/single-line-text.json"
     },
     "description": {
-      "$ref": "#/$defs/clean-prose"
-    }
-  },
-  "$defs": {
-    "clean-prose": {
-      "type": "string",
-      "not": {
-        "anyOf": [
-          {
-            "pattern": "\\.$"
-          },
-          {
-            "pattern": "  \\s"
-          },
-          {
-            "pattern": "[\\n\\r\\t]"
-          },
-          {
-            "pattern": "[\\x00-\\x1F\\x7F]"
-          }
-        ]
-      },
-      "pattern": "^[^\\s].*[^\\s]$|^[^\\s]$"
+      "$ref": "../schemas/misc/single-line-text.json"
     }
   }
 }
diff --git a/schemas/misc/single-line-text.json b/schemas/misc/single-line-text.json
new file mode 100644
index 00000000..99267427
--- /dev/null
+++ b/schemas/misc/single-line-text.json
@@ -0,0 +1,15 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "Single-line Text",
+  "description": "A string representing a single line of clean text without leading or trailing whitespace, excessive internal spacing, non-printable characters, newlines, tabs, trailing periods, or other punctuation issues",
+  "examples": [
+    "This is a simple text",
+    "Multiple sentences work fine",
+    "Numbers and symbols: 123 $%&",
+    "Unicode characters are allowed: café, 日本語"
+  ],
+  "x-license": "https://github.com/sourcemeta/std/blob/main/LICENSE",
+  "x-links": [ "https://en.wikipedia.org/wiki/String_(computer_science)" ],
+  "type": "string",
+  "pattern": "^(?!.*\\.$)(?!.*(?<!\\.)\\.\\.(?!\\.))(?!.* [.,;:!?])(?![?!])(?!.*[?!])(?!.*  )(?!.*\\(\\))(?!.*\\[\\])(?!.*--)(?!.*[\\n\\r\\t])(?!.*[\\x00-\\x1F\\x7F])[^\\s](?:.*[^\\s])?$"
+}
diff --git a/test/misc/single-line-text.test.json b/test/misc/single-line-text.test.json
new file mode 100644
index 00000000..a9b66068
--- /dev/null
+++ b/test/misc/single-line-text.test.json
@@ -0,0 +1,341 @@
+{
+  "x-license": "https://github.com/sourcemeta/std/blob/main/LICENSE",
+  "target": "../../schemas/misc/single-line-text.json",
+  "tests": [
+    {
+      "description": "Valid - simple text",
+      "data": "This is valid text",
+      "valid": true
+    },
+    {
+      "description": "Valid - single word",
+      "data": "Word",
+      "valid": true
+    },
+    {
+      "description": "Valid - single character",
+      "data": "a",
+      "valid": true
+    },
+    {
+      "description": "Valid - text with single spaces",
+      "data": "Multiple words with spaces",
+      "valid": true
+    },
+    {
+      "description": "Invalid - two consecutive spaces",
+      "data": "Two  spaces",
+      "valid": false
+    },
+    {
+      "description": "Valid - numbers and symbols",
+      "data": "Text with 123 and $%& symbols",
+      "valid": true
+    },
+    {
+      "description": "Valid - Unicode characters",
+      "data": "café 日本語 emoji 🎉",
+      "valid": true
+    },
+    {
+      "description": "Valid - multiple sentences without trailing period",
+      "data": "First sentence. Second sentence. Third one",
+      "valid": true
+    },
+    {
+      "description": "Valid - text with period in middle",
+      "data": "Dr. Smith works here",
+      "valid": true
+    },
+    {
+      "description": "Valid - abbreviations",
+      "data": "U.S.A. and U.K. are countries",
+      "valid": true
+    },
+    {
+      "description": "Invalid - trailing period",
+      "data": "Text with trailing period.",
+      "valid": false
+    },
+    {
+      "description": "Invalid - just a period",
+      "data": ".",
+      "valid": false
+    },
+    {
+      "description": "Invalid - leading whitespace",
+      "data": " Leading space",
+      "valid": false
+    },
+    {
+      "description": "Invalid - trailing whitespace",
+      "data": "Trailing space ",
+      "valid": false
+    },
+    {
+      "description": "Invalid - leading tab",
+      "data": "\tTabbed text",
+      "valid": false
+    },
+    {
+      "description": "Invalid - trailing tab",
+      "data": "Text with tab\t",
+      "valid": false
+    },
+    {
+      "description": "Invalid - tab in middle",
+      "data": "Text with\ttab",
+      "valid": false
+    },
+    {
+      "description": "Invalid - newline in middle",
+      "data": "Text with\nnewline",
+      "valid": false
+    },
+    {
+      "description": "Invalid - carriage return in middle",
+      "data": "Text with\rcarriage return",
+      "valid": false
+    },
+    {
+      "description": "Invalid - multiple newlines",
+      "data": "Line one\nLine two\nLine three",
+      "valid": false
+    },
+    {
+      "description": "Invalid - three consecutive spaces",
+      "data": "Three   spaces",
+      "valid": false
+    },
+    {
+      "description": "Invalid - four consecutive spaces",
+      "data": "Four    spaces",
+      "valid": false
+    },
+    {
+      "description": "Invalid - many consecutive spaces",
+      "data": "Many        spaces",
+      "valid": false
+    },
+    {
+      "description": "Invalid - null character",
+      "data": "Text with\u0000null",
+      "valid": false
+    },
+    {
+      "description": "Invalid - bell character",
+      "data": "Text with\u0007bell",
+      "valid": false
+    },
+    {
+      "description": "Invalid - backspace character",
+      "data": "Text with\bbackspace",
+      "valid": false
+    },
+    {
+      "description": "Invalid - form feed",
+      "data": "Text with\fform feed",
+      "valid": false
+    },
+    {
+      "description": "Invalid - vertical tab",
+      "data": "Text with\u000Bvertical tab",
+      "valid": false
+    },
+    {
+      "description": "Invalid - escape character",
+      "data": "Text with\u001Bescape",
+      "valid": false
+    },
+    {
+      "description": "Invalid - delete character",
+      "data": "Text withdelete",
+      "valid": false
+    },
+    {
+      "description": "Invalid - empty string",
+      "data": "",
+      "valid": false
+    },
+    {
+      "description": "Invalid - only whitespace",
+      "data": "   ",
+      "valid": false
+    },
+    {
+      "description": "Invalid - only tab",
+      "data": "\t",
+      "valid": false
+    },
+    {
+      "description": "Invalid - only newline",
+      "data": "\n",
+      "valid": false
+    },
+    {
+      "description": "Invalid type - number",
+      "data": 123,
+      "valid": false
+    },
+    {
+      "description": "Invalid type - boolean",
+      "data": true,
+      "valid": false
+    },
+    {
+      "description": "Invalid type - null",
+      "data": null,
+      "valid": false
+    },
+    {
+      "description": "Invalid type - array",
+      "data": [],
+      "valid": false
+    },
+    {
+      "description": "Invalid type - object",
+      "data": {},
+      "valid": false
+    },
+    {
+      "description": "Invalid - double period",
+      "data": "Text with.. double period",
+      "valid": false
+    },
+    {
+      "description": "Invalid - double period at end",
+      "data": "Text ends here..",
+      "valid": false
+    },
+    {
+      "description": "Valid - proper ellipsis",
+      "data": "Text with... ellipsis",
+      "valid": true
+    },
+    {
+      "description": "Valid - ellipsis in parentheses",
+      "data": "The duration component accepts designator format (P...) and weeks format (PnW)",
+      "valid": true
+    },
+    {
+      "description": "Invalid - space before period",
+      "data": "Text with space .",
+      "valid": false
+    },
+    {
+      "description": "Invalid - space before comma",
+      "data": "Text with space ,",
+      "valid": false
+    },
+    {
+      "description": "Invalid - space before semicolon",
+      "data": "Text with space ;",
+      "valid": false
+    },
+    {
+      "description": "Invalid - space before colon",
+      "data": "Text with space :",
+      "valid": false
+    },
+    {
+      "description": "Invalid - space before exclamation",
+      "data": "Text with space !",
+      "valid": false
+    },
+    {
+      "description": "Invalid - space before question mark",
+      "data": "Text with space ?",
+      "valid": false
+    },
+    {
+      "description": "Invalid - question mark at start",
+      "data": "?This is a question",
+      "valid": false
+    },
+    {
+      "description": "Invalid - exclamation mark at start",
+      "data": "!This is excitement",
+      "valid": false
+    },
+    {
+      "description": "Invalid - question mark in middle",
+      "data": "Text with ? question mark",
+      "valid": false
+    },
+    {
+      "description": "Invalid - exclamation mark in middle",
+      "data": "Text with ! exclamation",
+      "valid": false
+    },
+    {
+      "description": "Invalid - question mark at end",
+      "data": "Is this a question?",
+      "valid": false
+    },
+    {
+      "description": "Invalid - exclamation mark at end",
+      "data": "This is exciting!",
+      "valid": false
+    },
+    {
+      "description": "Invalid - double exclamation",
+      "data": "Very exciting!!",
+      "valid": false
+    },
+    {
+      "description": "Invalid - double question mark",
+      "data": "Really??",
+      "valid": false
+    },
+    {
+      "description": "Invalid - empty parentheses",
+      "data": "Text with () empty parens",
+      "valid": false
+    },
+    {
+      "description": "Invalid - empty brackets",
+      "data": "Text with [] empty brackets",
+      "valid": false
+    },
+    {
+      "description": "Invalid - double hyphen",
+      "data": "Text with -- double hyphen",
+      "valid": false
+    },
+    {
+      "description": "Valid - em dash",
+      "data": "Text with — em dash",
+      "valid": true
+    },
+    {
+      "description": "Valid - single hyphen",
+      "data": "Text with single-hyphen word",
+      "valid": true
+    },
+    {
+      "description": "Valid - parentheses with content",
+      "data": "Text with (content) in parens",
+      "valid": true
+    },
+    {
+      "description": "Valid - brackets with content",
+      "data": "Text with [content] in brackets",
+      "valid": true
+    },
+    {
+      "description": "Valid - proper comma usage",
+      "data": "First item, second item, third item",
+      "valid": true
+    },
+    {
+      "description": "Valid - proper colon usage",
+      "data": "Title: Subtitle",
+      "valid": true
+    },
+    {
+      "description": "Valid - proper semicolon usage",
+      "data": "First clause; second clause",
+      "valid": true
+    }
+  ]
+}