From 29c3189a681f77a51ff52d64c43fc5fe90314e7c Mon Sep 17 00:00:00 2001
From: Holger Vogt <holger.vogt@uni-due.de>
Date: Mon, 2 Jun 2025 11:59:18 +0200
Subject: [PATCH] Enable expressions in a meas statement within a .control
 section, like meas tran yeval2 FIND v(2) WHEN v(1)= 0.9*v(2)

---
 examples/measure/meas_expression.cir | 13 ++++++
 src/frontend/com_measure2.c          |  2 +-
 src/frontend/inpcom.c                | 68 ++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/examples/measure/meas_expression.cir b/examples/measure/meas_expression.cir
index 4954477c4..a3a77176c 100644
--- a/examples/measure/meas_expression.cir
+++ b/examples/measure/meas_expression.cir
@@ -14,6 +14,19 @@ run
 ** evaluate '0.9*v(2)' in control language command
 let vint = 0.9*v(2)
 meas tran yeval2 FIND v(2) WHEN v(1)= vint
+unlet vint
+
+* new expression evaluation
+meas tran yeval3 FIND v(2) WHEN v(1)= 0.9*v(2)
+
+* standard meas with val being a number:
+meas tran tdiff1 TRIG v(1) VAL=0.5 RISE=1 TARG v(1) VAL=0.5 RISE=3
+
+* expression evaluation with vector of length 1 only:
+let onevec = 1
+meas tran tdiff2 TRIG v(1) VAL=onevec-0.5 RISE=1 TARG v(1) VAL=onevec/2 RISE=3
+
+
 plot V(1) v(2)
 .endc
 
diff --git a/src/frontend/com_measure2.c b/src/frontend/com_measure2.c
index 9f314215b..1e7483501 100644
--- a/src/frontend/com_measure2.c
+++ b/src/frontend/com_measure2.c
@@ -64,7 +64,7 @@ is_arith_char2(char c)
     return c != '\0' && strchr("*/<>?:|&^!%\\", c);
 }
 
-static bool
+bool
 str_has_arith_char2(char* s)
 {
     if (*s == '+' || *s == '-')
diff --git a/src/frontend/inpcom.c b/src/frontend/inpcom.c
index 6fbc418fd..c3debe462 100644
--- a/src/frontend/inpcom.c
+++ b/src/frontend/inpcom.c
@@ -147,6 +147,7 @@ static void inp_compat(struct card *deck);
 static void inp_bsource_compat(struct card *deck);
 static bool inp_temper_compat(struct card *card);
 static void inp_meas_current(struct card *card);
+static void inp_meas_control(struct card *card);
 static void inp_dot_if(struct card *deck);
 static char *inp_modify_exp(char *expression);
 static struct func_temper *inp_new_func(char *funcname, char *funcbody,
@@ -1191,6 +1192,8 @@ struct card *inp_readall(FILE *fp, const char *dir_name, const char* file_name,
             inp_bsource_compat(working);
             inp_dot_if(working);
             expr_w_temper = inp_temper_compat(working);
+            /* check for expressions in meas command */
+            inp_meas_control(working);
         }
         if (expr_w_temper_p)
             *expr_w_temper_p = expr_w_temper;
@@ -9750,6 +9753,71 @@ int add_to_sourcepath(const char* filepath, const char* path)
     return 0;
 }
 
+/* if there is an expression in FIND ... WHEN etc in a .control section,
+   use a vector with this expression:
+   meas tran yeval2 FIND v(2) WHEN v(1)= 0.9*v(2)
+   will become
+   let vexprint1 = 0.9*v(2)
+   meas tran yeval2 FIND v(2) WHEN v(1)=vexprint1
+   unlet vint 
+*/
+static void inp_meas_control(struct card* card)
+{
+    int is_control = 0;
+    static int replaceno = 1;
+    struct card* prevcard;
+
+    for (; card; prevcard = card, card = card->nextcard) {
+
+        char* equal_ptr = NULL;
+        char* curr_line = card->line;
+        char* newcurrline = card->line;
+        int currlinenumber = card->linenum_orig;
+
+        /* only commands inside .control ... .endc */
+        if (ciprefix(".control", curr_line)) {
+            is_control++;
+            continue;
+        }
+        else if (ciprefix(".endc", curr_line)) {
+            is_control--;
+            continue;
+        }
+        else if (is_control < 1) {
+            continue;
+        }
+        curr_line = skip_ws(curr_line);
+        if (ciprefix("meas", curr_line) && (equal_ptr = find_assignment(curr_line)) != NULL) {
+            curr_line = equal_ptr + 1;
+            while (*curr_line != '\0' && equal_ptr) {
+                char* token = gettok(&curr_line);
+                if (str_has_arith_char(token)) {
+                    char* newtok = tprintf("=vexprint%d", replaceno++);
+                    char* begstr = copy_substring(newcurrline, equal_ptr);
+                    char* endstr = copy(curr_line);
+                    char* newline = tprintf("%s%s %s", begstr, newtok, endstr);
+                    char* letline = tprintf("let %s=%s", newtok + 1, token);
+                    char* unletline = tprintf("unlet %s", newtok + 1);
+                    tfree(newtok);
+                    tfree(begstr);
+                    tfree(endstr);
+                    prevcard = insert_new_line(prevcard, letline, 0, currlinenumber, card->linesource);
+                    card = prevcard->nextcard;
+                    tfree(card->line);
+                    card->line = newline;
+                    newcurrline = curr_line = card->line;
+                    card = insert_new_line(card, unletline, 0, currlinenumber, card->linesource);
+                }
+                tfree(token);
+                /* next equal sign in line */
+                equal_ptr = find_assignment(curr_line);
+                if (equal_ptr)
+                    curr_line = equal_ptr + 1;
+            }
+        }
+    }
+}
+
 
 #if defined(_WIN32)