diff --git a/src/structs.h b/src/structs.h
index ee56bd3..f978f61 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -75,6 +75,19 @@
 #endif
 
 /*
+ * SCript ConteXt (SCTX): identifies a script script line.
+ * When sourcing a script "sc_lnum" is zero, "sourcing_lnum" is the current
+ * line number. When executing a user function "sc_lnum" is the line where the
+ * function was defined, "sourcing_lnum" is the line number inside the
+ * function.  When stored with a function, mapping, option, etc. "sc_lnum" is
+ * the line number in the script "sc_sid".
+ */
+typedef struct {
+    scid_T	sc_sid;		// script ID
+    linenr_T	sc_lnum;	// line number
+} sctx_T;
+
+/*
  * Reference to a buffer that stores the value of buf_free_count.
  * bufref_valid() only needs to check "buf" when the count differs.
  */
@@ -278,8 +291,8 @@
 #endif
 
 #ifdef FEAT_EVAL
-    int		wo_scriptID[WV_COUNT];	/* SIDs for window-local options */
-# define w_p_scriptID w_onebuf_opt.wo_scriptID
+    sctx_T	wo_script_ctx[WV_COUNT];	/* SCTXs for window-local options */
+# define w_p_script_ctx w_onebuf_opt.wo_script_ctx
 #endif
 } winopt_T;
 
@@ -541,7 +554,7 @@
     int		xp_pattern_len;		/* bytes in xp_pattern before cursor */
 #if defined(FEAT_USR_CMDS) && defined(FEAT_EVAL) && defined(FEAT_CMDL_COMPL)
     char_u	*xp_arg;		/* completion function */
-    int		xp_scriptID;		/* SID for completion function */
+    sctx_T	xp_script_ctx;		/* SCTX for completion function */
 #endif
     int		xp_backslash;		/* one of the XP_BS_ values */
 #ifndef BACKSLASH_IN_FILENAME
@@ -1071,7 +1084,7 @@
     char	m_nowait;	/* <nowait> used */
 #ifdef FEAT_EVAL
     char	m_expr;		/* <expr> used, m_str is an expression */
-    scid_T	m_script_ID;	/* ID of script where map was defined */
+    sctx_T	m_script_ctx;		/* SCTX where map was defined */
 #endif
 };
 
@@ -1361,7 +1374,7 @@
     int		uf_tml_idx;	/* index of line being timed; -1 if none */
     int		uf_tml_execed;	/* line being timed was executed */
 #endif
-    scid_T	uf_script_ID;	/* ID of script where function was defined,
+    sctx_T	uf_script_ctx;	/* SCTX where function was defined,
 				   used for s: variables */
     int		uf_refcount;	/* reference count, see func_name_refcount() */
     funccall_T	*uf_scoped;	/* l: local variables for closure */
@@ -2123,7 +2136,7 @@
     int		b_p_initialized;	/* set when options initialized */
 
 #ifdef FEAT_EVAL
-    int		b_p_scriptID[BV_COUNT];	/* SIDs for buffer-local options */
+    sctx_T	b_p_script_ctx[BV_COUNT];	/* SCTXs for buffer-local options */
 #endif
 
     int		b_p_ai;		/* 'autoindent' */