[gnumeric] csv: improve handling of expressions.

[Morten Welinder <mortenw src gnome org>]

commit 0c4430052fb88f6d52e54f4c9fbcfa890e5cab2e
Author: Morten Welinder <terra gnome org>
Date:   Thu Oct 15 19:49:27 2020 -0400

    csv: improve handling of expressions.
    
    1. Ignore expression when guessing formats.
    2. Accept expressions in columns with non-general, non-text formats.

 ChangeLog       | 6 ++++++
 NEWS            | 1 +
 src/stf-parse.c | 5 +++--
 3 files changed, 10 insertions(+), 2 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 33db170c3..7aa3d3f43 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2020-10-15  Morten Welinder  <terra gnome org>
+
+       * src/stf-parse.c (stf_parse_sheet): Don't try to parse entries
+       with single quote or equal sign as numbers; use stf_cell_set_text.
+       (stf_parse_options_guess_formats): Skip entries with '=' also.
+
 2020-10-12  Morten Welinder  <terra gnome org>
 
        * src/workbook-priv.h: Introspection doesn't like empty structs so
diff --git a/NEWS b/NEWS
index 75c26566e..87b3e7ff6 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,7 @@ Morten:
        * Fix critical when using fd://1.
        * Don't trim spaces for csv files as per rfc 4180.  [#528]
        * Fix cvs separator guessing problem with quotes.  [#537]
+       * Improve handling of expressions in csv files.
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.48
diff --git a/src/stf-parse.c b/src/stf-parse.c
index 83493efd4..7a4332a05 100644
--- a/src/stf-parse.c
+++ b/src/stf-parse.c
@@ -1386,6 +1386,7 @@ stf_parse_sheet (StfParseOptions_t *parseoptions,
                        if (text && *text) {
                                GnmCell *cell = sheet_cell_fetch (sheet, col, row);
                                if (!go_format_is_text (fmt) &&
+                                   text[0] != '=' && text[0] != '\'' &&
                                    lcol < parseoptions->formats_decimal->len &&
                                    g_ptr_array_index (parseoptions->formats_decimal, lcol)) {
                                        GOFormatFamily fam;
@@ -1398,7 +1399,6 @@ stf_parse_sheet (StfParseOptions_t *parseoptions,
                                                v = value_new_string (text);
                                        sheet_cell_set_value (cell, v);
                                } else {
-
                                        stf_cell_set_text (cell, text);
                                }
                        }
@@ -2003,8 +2003,9 @@ stf_parse_options_guess_formats (StfParseOptions_t *po, char const *data)
                        GPtrArray *line = g_ptr_array_index (lines, lno);
                        const char *data = col < line->len ? g_ptr_array_index (line, col) : "";
                        unsigned prev_possible = possible;
+                       gunichar c0 = g_utf8_get_char (data);
 
-                       if (*data == 0 || data[0] == '\'')
+                       if (c0 == 0 || c0 == '\'' || c0 == '=')
                                continue;
 
                        do_check_date (data, STF_GUESS_DATE_DMY, FALSE, FALSE, &possible, date_conv);