From a5ec7dd7404029980fe2dd02b074775e1baaea9d Mon Sep 17 00:00:00 2001
From: Tyler Akins <fidian@rumkin.com>
Date: Fri, 3 Nov 2017 16:34:08 -0500
Subject: [PATCH] I think this finally implements arguments to functions

This closes #18.
---
 mo                           | 47 ++++++++++++++++++++++++++++++++----
 tests/function-args.env      | 16 ++++++++++++
 tests/function-args.expected |  4 +++
 tests/function-args.template |  4 +++
 4 files changed, 66 insertions(+), 5 deletions(-)
 create mode 100644 tests/function-args.env
 create mode 100644 tests/function-args.expected
 create mode 100644 tests/function-args.template

diff --git a/mo b/mo
index dbf61a7..51b3498 100755
--- a/mo
+++ b/mo
@@ -115,6 +115,24 @@ mo() (
 )
 
 
+# Internal: Call a function.
+#
+# $1 - Function to call
+# $2 - Content to pass
+# $3 - Additional arguments as a single string
+#
+# This can be dangerous, especially if you are using tags like
+# {{someFunction ; rm -rf / }}
+#
+# Returns nothing.
+moCallFunction() {
+    local moCommand
+
+    printf -v moCommand "%q %q %s" "$1" "$2" "$3"
+    eval "$moCommand"
+}
+
+
 # Internal: Scan content until the right end tag is found.  Creates an array
 # with the following members:
 #
@@ -567,7 +585,7 @@ moLoop() {
 moParse() {
     # Keep naming variables mo* here to not overwrite needed variables
     # used in the string replacements
-    local moBlock moContent moCurrent moIsBeginning moNextIsBeginning moTag
+    local moArgs moBlock moContent moCurrent moIsBeginning moNextIsBeginning moTag
 
     moCurrent=$2
     moIsBeginning=$3
@@ -585,6 +603,13 @@ moParse() {
                 # Sets context
                 moStandaloneAllowed moContent "${moContent[@]}" "$moIsBeginning"
                 moTrimWhitespace moTag "${moTag:1}"
+                
+                # Split arguments from the tag name. Arguments are passed to
+                # functions.
+                moArgs=$moTag
+                moTag=${moTag%% *}
+                moTag=${moTag%%$'\t'*}
+                moArgs=${moArgs:${#moTag}}
                 moFindEndTag moBlock "$moContent" "$moTag"
                 moFullTagName moTag "$moCurrent" "$moTag"
 
@@ -593,7 +618,7 @@ moParse() {
                     if moIsFunction "$moTag"; then
                         #: Consider piping the output to moGetContent
                         #: so the lambda does not execute in a subshell?
-                        moContent=$($moTag "${moBlock[0]}")
+                        moContent=$(moCallFunction "$moTag" "${moBlock[0]}" "$moArgs")
                         moParse "$moContent" "$moCurrent" false
                         moContent="${moBlock[2]}"
                     elif moIsArray "$moTag"; then
@@ -658,11 +683,16 @@ moParse() {
                 moContent="${moTag:1}"'}}'"$moContent"
                 moSplit moContent "$moContent" '}}}'
                 moTrimWhitespace moTag "${moContent[0]}"
+                moArgs=$moTag
+                moTag=${moTag%% *}
+                moTag=${moTag%%$'\t'*}
+                moArgs=${moArgs:${#moTag}}
                 moFullTagName moTag "$moCurrent" "$moTag"
                 moContent=${moContent[1]}
 
                 # Now show the value
-                moShow "$moTag" "$moCurrent"
+                # Quote moArgs here, do not quote it later.
+                moShow "$moTag" "$moCurrent" "$moArgs"
                 ;;
 
             '&'*)
@@ -676,8 +706,14 @@ moParse() {
             *)
                 # Normal environment variable or function call
                 moStandaloneDenied moContent "${moContent[@]}"
+                moArgs=$moTag
+                moTag=${moTag%% *}
+                moTag=${moTag%%$'\t'*}
+                moArgs=${moArgs:${#moTag}}
                 moFullTagName moTag "$moCurrent" "$moTag"
-                moShow "$moTag" "$moCurrent"
+
+                # Quote moArgs here, do not quote it later.
+                moShow "$moTag" "$moCurrent" "$moArgs"
                 ;;
         esac
 
@@ -763,6 +799,7 @@ moPartial() {
 #
 # $1 - Name of environment variable or function
 # $2 - Current context
+# $3 - Arguments string if $1 is a function
 #
 # Returns nothing.
 moShow() {
@@ -770,7 +807,7 @@ moShow() {
     local moJoined moNameParts
 
     if moIsFunction "$1"; then
-        CONTENT=$($1 "")
+        CONTENT=$(moCallFunction "$1" "" "$3")
         moParse "$CONTENT" "$2" false
         return 0
     fi
diff --git a/tests/function-args.env b/tests/function-args.env
new file mode 100644
index 0000000..ac98972
--- /dev/null
+++ b/tests/function-args.env
@@ -0,0 +1,16 @@
+name=Willy
+
+pipeTo() {
+    echo -n "$1" | "$2"
+}
+
+testArgs() {
+    printf "%d" "$#"
+
+    # Remove content. Note that when zero arguments are passed, this
+    # line does nothing and $1 will still be the content.
+    shift
+
+    # Display all arguments
+    printf " %q" "$@"
+}
diff --git a/tests/function-args.expected b/tests/function-args.expected
new file mode 100644
index 0000000..30eed40
--- /dev/null
+++ b/tests/function-args.expected
@@ -0,0 +1,4 @@
+No args: 1 '' - done
+One arg: 2 one - done
+Getting name in a string: 2 The\ name\ is\ Willy - done
+Reverse this: edcba
diff --git a/tests/function-args.template b/tests/function-args.template
new file mode 100644
index 0000000..889dfb8
--- /dev/null
+++ b/tests/function-args.template
@@ -0,0 +1,4 @@
+No args: {{testArgs}} - done
+One arg: {{testArgs one}} - done
+Getting name in a string: {{testArgs "The name is $name"}} - done
+Reverse this: {{#pipeTo rev}}abcde{{/pipeTo}}