Width and height argtypes, kdesc --argtypes from ref/, txt @define/@left_right/@columns, kdiag --check value validation (from dev d6993110e9b3)

Also: the klammertext argtype (descriptions kept as source), txt table
wrapping and :hpos/:offset, @c between ‹ ›, txt section headings, the
ktext newline-only trim, capitalize(), and the argtype test suite.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

sks/target/html_util.py

@@ -223,11 +223,11 @@ def hpos_container(element, hpos, offset=None):
     # coded, and only in html.)
     styles = []
     if hpos not in ("left", "center", "right", "none"):
-        length, _, _ = kutil.parse_length("html", hpos, 1)
+        length, _, _ = kutil.parse_width("html", hpos)
         styles.append(f"margin-left: {length}")
         hpos = "indent"
     if offset and offset not in ("0", "0pt") and hpos in ("left", "right", "indent"):
-        length, _, _ = kutil.parse_length("html", offset, 1)
+        length, _, _ = kutil.parse_width("html", offset)
         side = "right" if hpos == "right" else "left"
         styles.append(f"padding-{side}: {length}")
     result = E("div").cls("hpos_" + hpos).body(element)

sks/target/latex_util.py

@@ -81,9 +81,9 @@ def minipage(content, width="\\textwidth", vertical="c", center=True, vmargin=""
 
 def offset_length(offset):
     r"""An :offset as a LaTeX length, or "0pt" when there is none."""
-    if not offset or offset in ("0", "0pt"):
+    if not offset or offset in ("0", "0pt", "0.0"):
         return "0pt"
-    return kutil.parse_length("tex", offset, 1)[0]
+    return kutil.parse_width("tex", offset)[0]
 
 def offset_space(offset):
     r"""An :offset as an \hspace*, or "" when there is none."""
@@ -111,7 +111,7 @@ def caption_wrapper(element, hpos, bottom_margin=0, offset=None):
         return minipage("\\hfill" + element + inset, vmargin=vmargin, center=False)
     if hpos == "none":
         return element
-    length, _, _ = kutil.parse_length("tex", hpos, 1)
+    length, _, _ = kutil.parse_width("tex", hpos)
     return minipage(f"\\hspace*{{{length}}}" + element + "\\hfill",
                     vmargin=vmargin, center=False)
 

sks/target/phases.py

@@ -25,6 +25,26 @@ def txt_vspace_marker():
 def txt_nbsp_marker():
     return "__KTEXTNBSP__"
 
+# A ZERO-WIDTH mark that says "this line is already laid out" (2026-09-16).
+# The justification pass takes a paragraph beginning with a space or the
+# nbsp marker as verbatim, and until now that was the only way a block
+# could say so -- which broke the moment a block was flush left: a @table
+# with :hpos left :offset 0 (what @columns emits) began with its first
+# cell, so its rows were re-flowed into one line.  A block that lays itself
+# out puts this at the start of every line (txt_lay_out); it is nothing to
+# txt_visible_length and is removed at the end of txt_justify_blocks.
+def txt_verbatim_marker():
+    return "__KTEXTVERBATIM__"
+
+def txt_lay_out(text):
+    """text with every line marked as already laid out."""
+    mark = txt_verbatim_marker()
+    return "\n".join(mark + line for line in text.split("\n"))
+
+def txt_is_laid_out(par):
+    """True for a paragraph the justification pass must leave alone."""
+    return par.startswith((" ", txt_nbsp_marker(), txt_verbatim_marker()))
+
 # The type-style markers, emitted by @b.txt, @i.txt, @u.txt and @ri.txt
 # (sks/font/font.k) around their text.  Plain text has no bold, but a
 # terminal does: the txt target STRIPS these in its last phase
@@ -68,7 +88,7 @@ def txt_visible_length(s):
     """How many columns s occupies once its markers resolve: a KTESC
     marker is one glyph, an nbsp marker one space, a style marker nothing.
     len() is the wrong measure for anything laid out (see txt_util)."""
-    s = _STYLE_MARKER_RGX.sub("", s)
+    s = _STYLE_MARKER_RGX.sub("", s).replace(txt_verbatim_marker(), "")
     return len(klammer_base.unescape_ktesc(s).replace(txt_nbsp_marker(), " "))
 
 def txt_wrap(text, width, subsequent_indent=""):
@@ -159,7 +179,7 @@ def txt_justify_blocks(text, K):
         # branch that had nothing to do also did not copy the text through.
         # An indented paragraph vanished from the output with no error.
         nbsp = txt_nbsp_marker()
-        if par and par[0] != ' ' and not par.startswith(nbsp):
+        if par and not txt_is_laid_out(par):
             label = re.match("(?:" + re.escape(nbsp) + r")*\[\d+\] ", par)
             par = "\n".join(txt_wrap(
                 par, int(K.Target_txt_width),
@@ -167,6 +187,7 @@ def txt_justify_blocks(text, K):
         result += par + "\n\n"
     result = re.sub(" *" + txt_vspace_marker() + " *", "\n", result)
     result = re.sub(r"\n? *" + txt_nl_marker() + r" *\n?", "\n", result)
+    result = result.replace(txt_verbatim_marker(), "")
     result = result.replace(txt_nbsp_marker(), " ")
     return result
 

sks/target/target.k

@@ -38,7 +38,7 @@ of this: neither the transforms nor the quoting reach it.
 
 @@@state Target_txt_indent
   :desc Width of indentation in the plain text target (txt)
-  :value 3
+  :value 2
 @@@
 
 # The txt target is not fully implemented in the SKS yet.
@@ -59,7 +59,7 @@ of this: neither the transforms nor the quoting reach it.
   --- -- |
   ``  "  |
   ''  "  |
-  `   `  |
+  `   '  |
   '   '  |
   ~   __KTEXTNBSP__
   :after_apply