From 5c8699b7b0c48c5b9c40182b351da41b7887a5de Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Tue, 11 Oct 2022 20:41:28 -0700
Subject: streams: new function inc-indent-abs.

* stream.c (inc_indent_abs): New function.
(stream_init): inc-init-abs intrinsic registered.

* stream.h (inc_indent_abs): Declared.

* txr.1: Documented.

* stdlib/doc-syms.tl: Updated.
---
 stdlib/doc-syms.tl |  7 ++++---
 stream.c           | 13 +++++++++++++
 stream.h           |  1 +
 txr.1              | 13 ++++++++++++-
 4 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/stdlib/doc-syms.tl b/stdlib/doc-syms.tl
index 59535d41..e214011c 100644
--- a/stdlib/doc-syms.tl
+++ b/stdlib/doc-syms.tl
@@ -864,7 +864,7 @@
       ("get-fd" "N-011D42AB")
       ("get-frames" "N-010405DA")
       ("get-hash-userdata" "N-030B41A7")
-      ("get-indent" "N-024E9FD8")
+      ("get-indent" "N-00F72290")
       ("get-indent-mode" "N-03F3170C")
       ("get-json" "N-014295FE")
       ("get-jsons" "N-0124D378")
@@ -998,7 +998,8 @@
       ("inaddr-loopback" "N-026A2C3B")
       ("inaddr-str" "N-02456270")
       ("inc" "N-03A0AABD")
-      ("inc-indent" "N-024E9FD8")
+      ("inc-indent" "N-00F72290")
+      ("inc-indent-abs" "N-00F72290")
       ("include" "N-01A2ECA0")
       ("indent-code" "N-00512FDD")
       ("indent-data" "N-00512FDD")
@@ -1703,7 +1704,7 @@
       ("set-cflags" "N-02061924")
       ("set-hash-userdata" "N-030B40A7")
       ("set-iflags" "N-02061924")
-      ("set-indent" "N-024E9FD8")
+      ("set-indent" "N-00F72290")
       ("set-indent-mode" "N-03F3170C")
       ("set-key" "N-033F7D05")
       ("set-left" "N-033F7D05")
diff --git a/stream.c b/stream.c
index 08c2adc9..a3a70545 100644
--- a/stream.c
+++ b/stream.c
@@ -4104,6 +4104,18 @@ val inc_indent(val stream, val delta)
   return oldval;
 }
 
+val inc_indent_abs(val stream, val delta)
+{
+  val self = lit("inc-indent-abs");
+  struct strm_base *s = coerce(struct strm_base *,
+                               cobj_handle(self, stream, stream_cls));
+  val oldval = num(s->indent_chars);
+  s->indent_chars = c_num(plus(delta, oldval), self);
+  if (s->indent_chars < 0)
+    s->indent_chars = 0;
+  return oldval;
+}
+
 val width_check(val stream, val alt)
 {
   val self = lit("width-check");
@@ -5553,6 +5565,7 @@ void stream_init(void)
   reg_fun(intern(lit("get-indent"), user_package), func_n1(get_indent));
   reg_fun(intern(lit("set-indent"), user_package), func_n2(set_indent));
   reg_fun(intern(lit("inc-indent"), user_package), func_n2(inc_indent));
+  reg_fun(intern(lit("inc-indent-abs"), user_package), func_n2(inc_indent_abs));
   reg_fun(intern(lit("width-check"), user_package), func_n2(width_check));
   reg_fun(intern(lit("force-break"), user_package), func_n1(force_break));
   reg_fun(intern(lit("set-max-length"), user_package), func_n2(set_max_length));
diff --git a/stream.h b/stream.h
index 4d73bac1..428fa47c 100644
--- a/stream.h
+++ b/stream.h
@@ -236,6 +236,7 @@ val set_indent_mode(val stream, val mode);
 val get_indent(val stream);
 val set_indent(val stream, val indent);
 val inc_indent(val stream, val delta);
+val inc_indent_abs(val stream, val delta);
 val width_check(val stream, val alt);
 val force_break(val stream);
 val set_max_length(val stream, val length);
diff --git a/txr.1 b/txr.1
index 162545c4..be539219 100644
--- a/txr.1
+++ b/txr.1
@@ -62570,11 +62570,12 @@ if and only if the current mode is
 equal to
 .metn compare-mode .
 
-.coNP Functions @, get-indent @ set-indent and @ inc-indent
+.coNP Functions @, get-indent @, set-indent @ inc-indent and @ inc-indent-abs
 .synb
 .mets (get-indent << stream )
 .mets (set-indent < stream << new-indent )
 .mets (inc-indent < stream << indent-delta )
+.mets (inc-indent-abs < stream << indent-delta )
 .syne
 .desc
 These functions manipulate the indentation value of the stream.
@@ -62605,6 +62606,16 @@ The indentation is calculated by adding
 to the current column position.
 If a negative indentation results, it is clamped to zero.
 
+The
+.code inc-indent-abs
+function sets
+.metn stream 's
+indentation relative to the current indentation value.
+The indentation is calculated by adding
+.meta indent-delta
+to the current indentation amount.
+If a negative indentation results, it is clamped to zero.
+
 .coNP Function @ width-check
 .synb
 .mets (width-check < stream << alt-char )
-- 
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