Merge pull request #45 from yutachaos/feature/added_docker_release

Added dockerfile and release GitHub Action

.github/workflows/release.yaml

@@ -0,0 +1,45 @@
+name: docker push
+on: [push]
+jobs:
+  push_to_registry:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+      - name: Docker meta
+        if: startsWith(github.ref, 'refs/tags/')
+        id: docker_meta
+        uses: crazy-max/ghaction-docker-meta@v1
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tag-match: v(.*)
+      - name: Set up QEMU
+        if: startsWith(github.ref, 'refs/tags/')
+        uses: docker/setup-qemu-action@v1
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Cache Docker layers
+        if: startsWith(github.ref, 'refs/tags/')
+        uses: actions/cache@v2
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+      - name: Login to GitHub Container Registry
+        if: startsWith(github.ref, 'refs/tags/')
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name:  Build and push
+        uses: docker/build-push-action@v2
+        if: startsWith(github.ref, 'refs/tags/')
+        with:
+          builder: ${{ steps.buildx.outputs.name }}
+          platforms: linux/amd64,linux/arm64
+          tags: ${{ steps.docker_meta.outputs.tags }}
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache
+          push: true

API.md

@@ -4,21 +4,49 @@ API / Function Documentation
 This documentation is generated automatically from the source of [mo] thanks to [tomdoc.sh].
 
 
-mo()
-----
+`mo()`
+------
 
 Public: Template parser function.  Writes templates to stdout.
 
 * $0 - Name of the mo file, used for getting the help message.
-* --fail-not-set - Fail upon expansion of an unset variable.  Default behavior is to silently ignore and expand into empty string.
-* --false        - Treat "false" as an empty value.  You may set the MO_FALSE_IS_EMPTY environment variable instead to a non-empty value to enable this behavior.
-* --help         - Display a help message.
-* --source=FILE  - Source a file into the environment before processint template files.
-* --             - Used to indicate the end of options.  You may optionally use this when filenames may start with two hyphens.
 * $@ - Filenames to parse.
 
+Options:
+
+      --allow-function-arguments
+
+Permit functions in templates to be called with additional arguments.  This puts template data directly in to the path of an eval statement. Use with caution. Not listed in the help because it only makes sense when mo is sourced.
+
+      -u, --fail-not-set
+
+Fail upon expansion of an unset variable.  Default behavior is to silently ignore and expand into empty string.
+
+      -x, --fail-on-function
+
+Fail when a function used by a template returns an error status code. Alternately, ou may set the MO_FAIL_ON_FUNCTION environment variable to a non-empty value to enable this behavior.
+
+      -e, --false
+
+Treat "false" as an empty value.  You may set the MO_FALSE_IS_EMPTY environment variable instead to a non-empty value to enable this behavior.
+
+      -h, --help
+
+Display a help message.
+
+      -s=FILE, --source=FILE
+
+Source a file into the environment before processing template files. This can be used multiple times.
+
+      --
+
+Used to indicate the end of options.  You may optionally use this when filenames may start with two hyphens.
+
 Mo uses the following environment variables:
 
+* MO_ALLOW_FUNCTION_ARGUMENTS - When set to a non-empty value, this allows functions referenced in templates to receive additional options and arguments. This puts the content from the template directly into an eval statement. Use with extreme care.
+* MO_FUNCTION_ARGS - Arguments passed to the function
+* MO_FAIL_ON_FUNCTION - If a function returns a non-zero status code, abort with an error.
 * MO_FAIL_ON_UNSET - When set to a non-empty value, expansion of an unset env variable will be aborted with an error.
 * MO_FALSE_IS_EMPTY - When set to a non-empty value, the string "false" will be treated as an empty value for the purposes of conditionals.
 * MO_ORIGINAL_COMMAND - Used to find the `mo` program in order to generate a help message.
@@ -26,39 +54,24 @@ Mo uses the following environment variables:
 Returns nothing.
 
 
-files
------
+`moCallFunction()`
+------------------
 
-After we encounter two hyphens together, all the rest of the arguments are files.
+Internal: Call a function.
+
+* $1 - Variable for output
+* $2 - Function to call
+* $3 - Content to pass
+* $4 - Additional arguments as a single string
+
+This can be dangerous, especially if you are using tags like {{someFunction ; rm -rf / }}
+
+Returns nothing.
 
 
-MO_FAIL_ON_UNSET
+`moFindEndTag()`
 ----------------
 
-shellcheck disable=SC2030
-
-
-MO_FALSE_IS_EMPTY
------------------
-
-shellcheck disable=SC2030
-
-
-doubleHyphens
--------------
-
-Set a flag indicating we've encountered double hyphens
-
-
-files
------
-
-Every arg that is not a flag or a option should be a file
-
-
-moFindEndTag()
---------------
-
 Internal: Scan content until the right end tag is found.  Creates an array with the following members:
 
     [0] = Content before end tag
@@ -75,8 +88,8 @@ Everything using this function uses the "standalone tags" logic.
 Returns nothing.
 
 
-moFindString()
---------------
+`moFindString()`
+----------------
 
 Internal: Find the first index of a substring.  If not found, sets the index to -1.
 
@@ -87,8 +100,8 @@ Internal: Find the first index of a substring.  If not found, sets the index to
 Returns nothing.
 
 
-moFullTagName()
----------------
+`moFullTagName()`
+-----------------
 
 Internal: Generate a dotted name based on current context and target name.
 
@@ -99,8 +112,8 @@ Internal: Generate a dotted name based on current context and target name.
 Returns nothing.
 
 
-moGetContent()
---------------
+`moGetContent()`
+----------------
 
 Internal: Fetches the content to parse into a variable.  Can be a list of partials for files or the content from stdin.
 
@@ -110,8 +123,8 @@ Internal: Fetches the content to parse into a variable.  Can be a list of partia
 Returns nothing.
 
 
-moIndentLines()
----------------
+`moIndentLines()`
+-----------------
 
 Internal: Indent a string, placing the indent at the beginning of every line that has any content.
 
@@ -122,8 +135,8 @@ Internal: Indent a string, placing the indent at the beginning of every line tha
 Returns nothing.
 
 
-moIndirect()
-------------
+`moIndirect()`
+--------------
 
 Internal: Send a variable up to the parent of the caller of this function.
 
@@ -141,8 +154,8 @@ Examples
 Returns nothing.
 
 
-moIndirectArray()
------------------
+`moIndirectArray()`
+-------------------
 
 Internal: Send an array as a variable up to caller of a function
 
@@ -161,8 +174,8 @@ Examples
 Returns nothing.
 
 
-moIsArray()
------------
+`moIsArray()`
+-------------
 
 Internal: Determine if a given environment variable exists and if it is an array.
 
@@ -173,16 +186,16 @@ Be extremely careful.  Even if strict mode is enabled, it is not honored in newe
 Examples
 
     var=(abc)
-    if moIsArray var; the
+    if moIsArray var; then
        echo "This is an array"
-       echo "Make sure you don't accidentally use $var"
+       echo "Make sure you don't accidentally use \$var"
     fi
 
 Returns 0 if the name is not empty, 1 otherwise.
 
 
-moIsFunction()
---------------
+`moIsFunction()`
+----------------
 
 Internal: Determine if the given name is a defined function.
 
@@ -202,8 +215,8 @@ Examples
 Returns 0 if the name is a function, 1 otherwise.
 
 
-moIsStandalone()
-----------------
+`moIsStandalone()`
+------------------
 
 Internal: Determine if the tag is a standalone tag based on whitespace before and after the tag.
 
@@ -223,8 +236,8 @@ Examples
 Returns nothing.
 
 
-moJoin()
---------
+`moJoin()`
+----------
 
 Internal: Join / implode an array
 
@@ -235,19 +248,19 @@ Internal: Join / implode an array
 Returns nothing.
 
 
-moLoadFile()
-------------
+`moLoadFile()`
+--------------
 
 Internal: Read a file into a variable.
 
 * $1 - Variable name to receive the file's content
-* $2 - Filename to load
+* $2 - Filename to load - if empty, defaults to /dev/stdin
 
 Returns nothing.
 
 
-moLoop()
---------
+`moLoop()`
+----------
 
 Internal: Process a chunk of content some number of times.  Writes output to stdout.
 
@@ -258,8 +271,8 @@ Internal: Process a chunk of content some number of times.  Writes output to std
 Returns nothing.
 
 
-moParse()
----------
+`moParse()`
+-----------
 
 Internal: Parse a block of text, writing the result to stdout.
 
@@ -270,8 +283,14 @@ Internal: Parse a block of text, writing the result to stdout.
 Returns nothing.
 
 
-moPartial()
------------
+`moArgs`
+--------
+
+Split arguments from the tag name. Arguments are passed to functions.
+
+
+`moPartial()`
+-------------
 
 Internal: Process a partial.
 
@@ -291,8 +310,8 @@ Prefix all variables.
 Returns nothing.
 
 
-moShow()
---------
+`moShow()`
+----------
 
 Internal: Show an environment variable or the output of a function to stdout.
 
@@ -300,12 +319,13 @@ Limit/prefix any variables used.
 
 * $1 - Name of environment variable or function
 * $2 - Current context
+* $3 - Arguments string if $1 is a function
 
 Returns nothing.
 
 
-moSplit()
----------
+`moSplit()`
+-----------
 
 Internal: Split a larger string into an array.
 
@@ -317,8 +337,8 @@ Internal: Split a larger string into an array.
 Returns nothing.
 
 
-moStandaloneAllowed()
----------------------
+`moStandaloneAllowed()`
+-----------------------
 
 Internal: Handle the content for a standalone tag.  This means removing whitespace (not newlines) before a tag and whitespace and a newline after a tag.  That is, assuming, that the line is otherwise empty.
 
@@ -331,8 +351,8 @@ Internal: Handle the content for a standalone tag.  This means removing whitespa
 Returns nothing.
 
 
-moStandaloneDenied()
---------------------
+`moStandaloneDenied()`
+----------------------
 
 Internal: Handle the content for a tag that is never "standalone".  No adjustments are made for newlines and whitespace.
 
@@ -344,8 +364,8 @@ Internal: Handle the content for a tag that is never "standalone".  No adjustmen
 Returns nothing.
 
 
-moTest()
---------
+`moTest()`
+----------
 
 Internal: Determines if the named thing is a function or if it is a non-empty environment variable.  When MO_FALSE_IS_EMPTY is set to a non-empty value, then "false" is also treated is an empty value.
 
@@ -358,8 +378,8 @@ Do not use variables without prefixes here if possible as this needs to check if
 Returns 0 if the name is not empty, 1 otherwise.  When MO_FALSE_IS_EMPTY is set, this returns 1 if the name is "false".
 
 
-moTestVarSet()
---------------
+`moTestVarSet()`
+----------------
 
 Internal: Determine if a variable is assigned, even if it is assigned an empty value.
 
@@ -368,8 +388,8 @@ Internal: Determine if a variable is assigned, even if it is assigned an empty v
 Returns true (0) if the variable is set, 1 if the variable is unset.
 
 
-moTrimChars()
--------------
+`moTrimChars()`
+---------------
 
 Internal: Trim the leading whitespace only.
 
@@ -382,8 +402,8 @@ Internal: Trim the leading whitespace only.
 Returns nothing.
 
 
-moTrimWhitespace()
-------------------
+`moTrimWhitespace()`
+--------------------
 
 Internal: Trim leading and trailing whitespace from a string.
 
@@ -393,8 +413,8 @@ Internal: Trim leading and trailing whitespace from a string.
 Returns nothing.
 
 
-moUsage()
----------
+`moUsage()`
+-----------
 
 Internal: Displays the usage for mo.  Pulls this from the file that contained the `mo` function.  Can only work when the right filename comes is the one argument, and that only happens when `mo` is called with `$0` set to this file.
 
@@ -403,11 +423,11 @@ Internal: Displays the usage for mo.  Pulls this from the file that contained th
 Returns nothing.
 
 
-MO_ORIGINAL_COMMAND
--------------------
+`MO_ORIGINAL_COMMAND`
+---------------------
 
 Save the original command's path for usage later
 
 
 [mo]: ./mo
-[tomdoc.sh]: https://github.com/mlafeldt/tomdoc.sh
+[tomdoc.sh]: https://github.com/tests-always-included/tomdoc.sh

Dockerfile

@@ -0,0 +1,11 @@
+FROM alpine:3.13.4
+
+COPY ./mo .
+RUN apk add --update bash && \
+    chmod +x mo &&\
+    mv mo /usr/local/bin/mo && \
+    rm -rf /var/cache/apk/*
+
+WORKDIR /opt
+
+ENTRYPOINT ["/usr/local/bin/mo"]

README.md

@@ -41,7 +41,7 @@ There are a few ways you can install this tool.  How you install it depends on h
 You can install this file in `/usr/local/bin/` or `/usr/bin/` by simply downloading it, changing the permissions, then moving it to the right location.  Double check that your system's PATH includes the destination folder, otherwise users may have a hard time starting the command.
 
     # Download
-    curl -sSO https://raw.githubusercontent.com/tests-always-included/mo/master/mo
+    curl -sSL https://git.io/get-mo -o mo
 
     # Make executable
     chmod +x mo
@@ -58,7 +58,7 @@ You can install this file in `/usr/local/bin/` or `/usr/bin/` by simply download
 This is very similar to installing it globally but it does not require root privileges.  It is very important that your PATH includes the destination folder otherwise it won't work.  Some local folders that are typically used are `~/bin/` and `~/.local/bin/`.
 
     # Download
-    curl -sSO https://raw.githubusercontent.com/tests-always-included/mo/master/mo
+    curl -sSL https://git.io/get-mo -o mo
 
     # Make executable
     chmod +x mo
@@ -78,7 +78,7 @@ This is very similar to installing it globally but it does not require root priv
 Bash scripts can source `mo` to include the functionality in their own routines.  This usage typically would have `mo` saved to a `lib/` folder in an application and your other scripts would use `. lib/mo` to bring it into your project.
 
     # Download
-    curl -sSO https://raw.githubusercontent.com/tests-always-included/mo/master/mo
+    curl -sSL https://git.io/get-mo -o mo
 
     # Move into your project folder
     mv mo ~/projects/amazing-things/lib/
@@ -115,6 +115,8 @@ The result?  You get a list of the five elements in the array.  It is vital that
 
 There are more scripts available in the [demos directory](demo/) that could help illustrate how you would use this program.
 
+There are additional features that the program supports. Try using `mo --help` to see what is available.
+
 
 Concessions
 -----------

demo/function-args

@@ -0,0 +1,29 @@
+#!/bin/bash
+#
+# This sources a simple script with the env. variables needed for the template.
+
+cd "$(dirname "$0")" # Go to the script's directory
+source ../mo
+
+export NAME="Alex"
+export ARRAY=( AAA BBB CCC )
+
+# Include an external template
+INCLUDE() {
+    cat "$MO_FUNCTION_ARGS"
+}
+
+# Print section title
+TITLE() {
+    echo "+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+"
+    echo "$MO_FUNCTION_ARGS"
+    echo "+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+"
+}
+
+cat <<EOF | mo -u
+{{TITLE Part 1}}
+{{INCLUDE function-args-part1}}
+
+{{TITLE Part 2}}
+{{INCLUDE function-args-part2}}
+EOF

demo/function-args-part1

@@ -0,0 +1 @@
+Hello, my name is {{NAME}}.

demo/function-args-part2

@@ -0,0 +1,3 @@
+{{#ARRAY}}
+    * {{.}}
+{{/ARRAY}}

demo/function-for-advanced-looping

@@ -3,6 +3,9 @@
 cd "$(dirname "$0")" # Go to the script's directory
 
 EVERY_REPO() {
+    # The block contents come in through standard input. Capture it here.
+    content=$(cat)
+
     echo "# Starting EVERY_REPO"
 
     # Get list of repos
@@ -14,7 +17,7 @@ EVERY_REPO() {
         # It rewrites {{__REPO__.name}} into {{resque.name}}, for instance.
         # You can prefix your environment variables and do other things as well.
         
-        echo -n "$1" | sed "s/__REPO__/${REPO}/"
+        echo "$content" | sed "s/__REPO__/${REPO}/"
 
         echo "## Looped one time for repo: $REPO"
     done

demo/function-for-building-json

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+cd "$(dirname "$0")" # Go to the script's directory
+
+# Detect if this is the first item and write a comma if it is.
+# Normally, I would track this using a variable, like so:
+#
+# COMMA_IF_NOT_FIRST_FLAG=false
+# COMMA_IF_NOT_FIRST() {
+#     $COMMA_IF_NOT_FIRST || echo ","
+#     COMMA_IF_NOT_FIRST_FLAG=true
+# }
+#
+# Since this function executes in a subshell, that approach will not work.
+# Instead, we peek inside mo and see what is being processed. If the variable
+# name in moParse() changes, this will need to get updated as well. An
+# alternate variable that is usable is context, but that is in moLoop() and is
+# two levels levels deep instead of just one.
+COMMA_IF_NOT_FIRST() {
+    [[ "${moCurrent#*.}" != "0" ]] && echo ","
+}
+
+# Create an array that will be embedded into the JSON. If you are manipulating
+# JSON, might I suggest you look at using jq? It's really good at processing
+# JSON.
+items=(
+    '{"position":"one","url":"1"}'
+    '{"position":"two","url":"2"}'
+    '{"position":"three","url":"3"}'
+)
+. ../mo
+cat <<EOF | mo
+{
+    {{#items}}
+    {{COMMA_IF_NOT_FIRST}}
+    {{.}}
+    {{/items}}
+}
+EOF

demo/function-for-foreach

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+# Example for how #29 can get implemented.
+
+cd "$(dirname "$0")" # Go to the script's directory
+
+foreach() {
+    # Trying to use unique names
+    local foreachSourceName foreachIterator foreachEvalString foreachContent
+
+    foreachContent=$(cat)
+
+    if [[ "$2" != "as" && "$2" != "in" ]]; then
+        echo "Invalid foreach - bad format."
+    elif [[ "$(declare -p "$1")" != "declare -"[aA]* ]]; then
+        echo "$1 is not an array"
+    else
+        foreachSourceName="${1}[@]"
+
+        for foreachIterator in "${!foreachSourceName}"; do
+            foreachEvalString=$(declare -p "$foreachIterator")
+            foreachEvalString="declare -A $3=${foreachEvalString#*=}"
+            eval "$foreachEvalString"
+            echo "$foreachContent" | mo
+        done
+    fi
+}
+
+
+# The links are associative arrays
+declare -A resque hub rip
+resque=([name]=Resque [url]=http://example.com/resque)
+hub=([name]=Hub [url]=http://example.com/hub)
+rip=([name]=Rip [url]=http://example.com/rip)
+
+# This is a list of the link arrays
+links=(resque hub rip)
+
+# Source mo in order to work with arrays
+. ../mo
+
+# Process the template
+cat <<EOF | mo --allow-function-arguments
+Here are your links:
+{{#foreach links as link}}
+ * [{{link.name}}]({{link.url}})
+{{/foreach}}
+
+EOF

demo/important-file

@@ -2,13 +2,17 @@
 
 cd "$(dirname "$0")"/..
 
-date-string() { date; }
-wrapper() { echo -n "*** $1 ***"; }
+date-string() {
+    date
+}
+wrapper() {
+    echo -n "*** $(cat) ***"
+}
 
 export IP=127.0.0.1
 export ALLOWED_HOSTS=( 192.168.0.1 192.168.0.2 192.168.0.3 )
 
-. mo  # Keep in mind this script is executing in the parent directory
+. ./mo  # Keep in mind this script is executing in the parent directory
 cat <<EOF | mo
 # {{#wrapper}}OH SO IMPORTANT{{/wrapper}}
 # This file automatically generated at {{date-string}}

demo/writing-out-braces

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+cd "$(dirname "$0")" # Go to the script's directory
+
+
+export OPEN="{{"
+export CLOSE="}}"
+cat <<'EOF' | mo
+You can use environment variables to write output that has double braces.
+
+    {{OPEN}}sampleTag{{CLOSE}}
+EOF

diagnostic

@@ -10,11 +10,12 @@
 # diagnose what's not working and fix those low-level functions first.
 
 PARENT_PID=$$
-cd "$(dirname "$0")"
+cd "$(dirname "$0")" || exit 1
 rm -f diagnostic.test
 rm -f diagnostic.partial
 
 # Load mo's functions
+# shellcheck disable=SC1091
 . ./mo
 
 fail() {
@@ -75,21 +76,20 @@ echo "ok"
 
 echo -n "moIsArray ... "
 (
-    TEST=1
-    moIsArray TEST && fail "Wrongly said number was an array"
+    export TEST_NUM=1
+    moIsArray TEST_NUM && fail "Wrongly said number was an array"
 )
 (
-    TEST=()
-    moIsArray TEST || fail "Wrongly said array was not an array"
+    export TEST_ARR=()
+    moIsArray TEST_ARR || fail "Wrongly said array was not an array"
 )
 (
-    # shellcheck disable=SC2034
-    TEST=""
-    moIsArray TEST && fail "Wrongly said string was an array"
+    export TEST_EMPTY=""
+    moIsArray TEST_EMPTY && fail "Wrongly said string was an array"
 )
 (
-    unset TEST
-    moIsArray TEST && fail "Wrongly said undefined was an array"
+    unset TEST_UNSET
+    moIsArray TEST_UNSET && fail "Wrongly said undefined was an array"
 )
 echo "ok"
 

make-api-doc

@@ -1,9 +1,9 @@
 #!/bin/bash
 #
 # This requires tomdoc.sh to be in your PATH.
-# https://github.com/mlafeldt/tomdoc.sh
+# https://github.com/tests-always-included/tomdoc.sh
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 
 cat <<'EOF'
 API / Function Documentation
@@ -13,8 +13,8 @@ This documentation is generated automatically from the source of [mo] thanks to
 
 
 EOF
-tomdoc.sh -m mo
+sed 's/# shellcheck.*//' mo | tomdoc.sh -m
 cat <<'EOF'
 [mo]: ./mo
-[tomdoc.sh]: https://github.com/mlafeldt/tomdoc.sh
+[tomdoc.sh]: https://github.com/tests-always-included/tomdoc.sh
 EOF

mo

@@ -11,12 +11,21 @@
 #/
 #/ Simple usage:
 #/
-#/    mo [--false] [--help] [--source=FILE] filenames...
+#/    mo [OPTIONS] filenames...
 #/
-#/ --fail-not-set - Fail upon expansion of an unset variable.
-#/ --false        - Treat the string "false" as empty for conditionals.
-#/ --help         - This message.
-#/ --source=FILE  - Load FILE into the environment before processing templates.
+#/ Options:
+#/
+#/    -u, --fail-not-set
+#/          Fail upon expansion of an unset variable.
+#/    -x, --fail-on-function
+#/          Fail when a function returns a non-zero status code.
+#/    -e, --false
+#/          Treat the string "false" as empty for conditionals.
+#/    -h, --help
+#/          This message.
+#/    -s=FILE, --source=FILE
+#/          Load FILE into the environment before processing templates.
+#/          Can be used multiple times.
 #
 # Mo is under a MIT style licence with an additional non-advertising clause.
 # See LICENSE.md for the full text.
@@ -29,27 +38,63 @@
 # Public: Template parser function.  Writes templates to stdout.
 #
 # $0 - Name of the mo file, used for getting the help message.
-# --fail-not-set - Fail upon expansion of an unset variable.  Default behavior
-#                  is to silently ignore and expand into empty string.
-# --false        - Treat "false" as an empty value.  You may set the
-#                  MO_FALSE_IS_EMPTY environment variable instead to a non-empty
-#                  value to enable this behavior.
-# --help         - Display a help message.
-# --source=FILE  - Source a file into the environment before processint
-#                  template files.
-# --             - Used to indicate the end of options.  You may optionally
-#                  use this when filenames may start with two hyphens.
 # $@ - Filenames to parse.
 #
+# Options:
+#
+#     --allow-function-arguments
+#
+# Permit functions in templates to be called with additional arguments.  This
+# puts template data directly in to the path of an eval statement. Use with
+# caution. Not listed in the help because it only makes sense when mo is
+# sourced.
+#
+#     -u, --fail-not-set
+#
+# Fail upon expansion of an unset variable.  Default behavior is to silently
+# ignore and expand into empty string.
+#
+#     -x, --fail-on-function
+#
+# Fail when a function used by a template returns an error status code.
+# Alternately, ou may set the MO_FAIL_ON_FUNCTION environment variable to a
+# non-empty value to enable this behavior.
+#
+#     -e, --false
+#
+# Treat "false" as an empty value.  You may set the MO_FALSE_IS_EMPTY
+# environment variable instead to a non-empty value to enable this behavior.
+#
+#     -h, --help
+#
+# Display a help message.
+#
+#     -s=FILE, --source=FILE
+#
+# Source a file into the environment before processing template files.
+# This can be used multiple times.
+#
+#     --
+#
+# Used to indicate the end of options.  You may optionally use this when
+# filenames may start with two hyphens.
+#
 # Mo uses the following environment variables:
 #
-# MO_FAIL_ON_UNSET    - When set to a non-empty value, expansion of an unset
-#                       env variable will be aborted with an error.
-# MO_FALSE_IS_EMPTY   - When set to a non-empty value, the string "false"
-#                       will be treated as an empty value for the purposes
-#                       of conditionals.
-# MO_ORIGINAL_COMMAND - Used to find the `mo` program in order to generate
-#                       a help message.
+# MO_ALLOW_FUNCTION_ARGUMENTS - When set to a non-empty value, this allows
+#                  functions referenced in templates to receive additional
+#                  options and arguments. This puts the content from the
+#                  template directly into an eval statement. Use with extreme
+#                  care.
+# MO_FUNCTION_ARGS - Arguments passed to the function
+# MO_FAIL_ON_FUNCTION - If a function returns a non-zero status code, abort
+#                  with an error.
+# MO_FAIL_ON_UNSET - When set to a non-empty value, expansion of an unset env
+#                  variable will be aborted with an error.
+# MO_FALSE_IS_EMPTY - When set to a non-empty value, the string "false" will be
+#                  treated as an empty value for the purposes of conditionals.
+# MO_ORIGINAL_COMMAND - Used to find the `mo` program in order to generate a
+#                  help message.
 #
 # Returns nothing.
 mo() (
@@ -64,8 +109,8 @@ mo() (
     if [[ $# -gt 0 ]]; then
         for arg in "$@"; do
             if $doubleHyphens; then
-                # After we encounter two hyphens together, all the rest
-                # of the arguments are files.
+                #: After we encounter two hyphens together, all the rest
+                #: of the arguments are files.
                 files=("${files[@]}" "$arg")
             else
                 case "$arg" in
@@ -74,18 +119,32 @@ mo() (
                         exit 0
                         ;;
 
-                    --fail-not-set)
+                    --allow-function-arguments)
+                        # shellcheck disable=SC2030
+                        MO_ALLOW_FUNCTION_ARGUMENTS=true
+                        ;;
+
+                    -u | --fail-not-set)
                         # shellcheck disable=SC2030
                         MO_FAIL_ON_UNSET=true
                         ;;
 
-                    --false)
+                    -x | --fail-on-function)
+                        # shellcheck disable=SC2030
+                        MO_FAIL_ON_FUNCTION=true
+                        ;;
+
+                    -e | --false)
                         # shellcheck disable=SC2030
                         MO_FALSE_IS_EMPTY=true
                         ;;
 
-                    --source=*)
+                    -s=* | --source=*)
+                        if [[ "$arg" == --source=* ]]; then
                             f2source="${arg#--source=}"
+                        else
+                            f2source="${arg#-s=}"
+                        fi
 
                         if [[ -f "$f2source" ]]; then
                             # shellcheck disable=SC1090
@@ -97,12 +156,12 @@ mo() (
                         ;;
 
                     --)
-                        # Set a flag indicating we've encountered double hyphens
+                        #: Set a flag indicating we've encountered double hyphens
                         doubleHyphens=true
                         ;;
 
                     *)
-                        # Every arg that is not a flag or a option should be a file
+                        #: Every arg that is not a flag or a option should be a file
                         files=(${files[@]+"${files[@]}"} "$arg")
                         ;;
                 esac
@@ -115,6 +174,44 @@ mo() (
 )
 
 
+# Internal: Call a function.
+#
+# $1 - Variable for output
+# $2 - Function to call
+# $3 - Content to pass
+# $4 - Additional arguments as a single string
+#
+# This can be dangerous, especially if you are using tags like
+# {{someFunction ; rm -rf / }}
+#
+# Returns nothing.
+moCallFunction() {
+    local moArgs moContent moFunctionArgs moFunctionResult
+
+    moArgs=()
+    moTrimWhitespace moFunctionArgs "$4"
+
+    # shellcheck disable=SC2031
+    if [[ -n "${MO_ALLOW_FUNCTION_ARGUMENTS-}" ]]; then
+        # Intentionally bad behavior
+        # shellcheck disable=SC2206
+        moArgs=($4)
+    fi
+
+    moContent=$(echo -n "$3" | MO_FUNCTION_ARGS="$moFunctionArgs" eval "$2" "${moArgs[@]}") || {
+        moFunctionResult=$?
+        # shellcheck disable=SC2031
+        if [[ -n "${MO_FAIL_ON_FUNCTION-}" && "$moFunctionResult" != 0 ]]; then
+            echo "Function '$2' with args (${moArgs[*]+"${moArgs[@]}"}) failed with status code $moFunctionResult"
+            exit "$moFunctionResult"
+        fi
+    }
+
+    # shellcheck disable=SC2031
+    local "$1" && moIndirect "$1" "$moContent"
+}
+
+
 # Internal: Scan content until the right end tag is found.  Creates an array
 # with the following members:
 #
@@ -163,6 +260,7 @@ moFindEndTag() {
                     if [[ -z "${4-}" ]] && moIsStandalone standaloneBytes "$scanned" "${content[2]}" true; then
                         #: This is also a standalone tag - clean up whitespace
                         #: and move those whitespace bytes to the "tag" element
+                        # shellcheck disable=SC2206
                         standaloneBytes=( $standaloneBytes )
                         content[1]="${scanned:${standaloneBytes[0]}}${content[1]}${content[2]:0:${standaloneBytes[1]}}"
                         scanned="${scanned:0:${standaloneBytes[0]}}"
@@ -234,22 +332,22 @@ moFullTagName() {
 #
 # Returns nothing.
 moGetContent() {
-    local content filename target
+    local moContent moFilename moTarget
 
-    target=$1
+    moTarget=$1
     shift
     if [[ "${#@}" -gt 0 ]]; then
-        content=""
+        moContent=""
 
-        for filename in "$@"; do
+        for moFilename in "$@"; do
             #: This is so relative paths work from inside template files
-            content="$content"'{{>'"$filename"'}}'
+            moContent="$moContent"'{{>'"$moFilename"'}}'
         done
     else
-        moLoadFile content /dev/stdin || return 1
+        moLoadFile moContent || return 1
     fi
 
-    local "$target" && moIndirect "$target" "$content"
+    local "$moTarget" && moIndirect "$moTarget" "$moContent"
 }
 
 
@@ -424,6 +522,7 @@ moIsFunction() {
     local functionList functionName
 
     functionList=$(declare -F)
+    # shellcheck disable=SC2206
     functionList=( ${functionList//declare -f /} )
 
     for functionName in "${functionList[@]}"; do
@@ -515,7 +614,7 @@ moJoin() {
 # Internal: Read a file into a variable.
 #
 # $1 - Variable name to receive the file's content
-# $2 - Filename to load
+# $2 - Filename to load - if empty, defaults to /dev/stdin
 #
 # Returns nothing.
 moLoadFile() {
@@ -526,7 +625,7 @@ moLoadFile() {
     # As a future optimization, it would be worth considering removing
     # cat and replacing this with a read loop.
 
-    content=$(cat -- "$2" && echo '.') || return 1
+    content=$(cat -- "${2:-/dev/stdin}" && echo '.') || return 1
     len=$((${#content} - 1))
     content=${content:0:$len}  # Remove last dot
 
@@ -567,7 +666,7 @@ 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=$3
@@ -585,15 +684,20 @@ moParse() {
                 # Sets context
                 moStandaloneAllowed moContent "${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"
 
                 if moTest "$moTag"; then
                     # Show / loop / pass through function
                     if moIsFunction "$moTag"; then
-                        #: Consider piping the output to moGetContent
-                        #: so the lambda does not execute in a subshell?
-                        moContent=$($moTag "${moBlock[0]}")
+                        moCallFunction moContent "$moTag" "${moBlock[0]}" "$moArgs"
                         moParse "$moContent" "$moCurrent" false
                         moContent="${moBlock[2]}"
                     elif moIsArray "$moTag"; then
@@ -658,11 +762,16 @@ 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 +785,14 @@ 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
 
@@ -715,6 +830,7 @@ moPartial() {
     local moContent moFilename moIndent moIsBeginning moPartial moStandalone moUnindented
 
     if moIsStandalone moStandalone "$2" "$4" "$5"; then
+        # shellcheck disable=SC2206
         moStandalone=( $moStandalone )
         echo -n "${2:0:${moStandalone[0]}}"
         moIndent=${2:${moStandalone[0]}}
@@ -763,29 +879,30 @@ moPartial() {
 #
 # $1 - Name of environment variable or function
 # $2 - Current context
+# $3 - Arguments string if $1 is a function
 #
 # Returns nothing.
 moShow() {
     # Namespace these variables
-    local moJoined moNameParts
+    local moJoined moNameParts moContent
 
     if moIsFunction "$1"; then
-        CONTENT=$($1 "")
-        moParse "$CONTENT" "$2" false
+        moCallFunction moContent "$1" "" "$3"
+        moParse "$moContent" "$2" false
         return 0
     fi
 
     moSplit moNameParts "$1" "."
 
-    if [[ -z "${moNameParts[1]}" ]]; then
+    if [[ -z "${moNameParts[1]-}" ]]; then
         if moIsArray "$1"; then
             eval moJoin moJoined "," "\${$1[@]}"
             echo -n "$moJoined"
         else
             # shellcheck disable=SC2031
-            if [[ -z "$MO_FAIL_ON_UNSET" ]] || moTestVarSet "$1"; then
+            if moTestVarSet "$1"; then
                 echo -n "${!1}"
-            else
+            elif [[ -n "${MO_FAIL_ON_UNSET-}" ]]; then
                 echo "Env variable not set: $1" >&2
                 exit 1
             fi
@@ -846,6 +963,7 @@ moStandaloneAllowed() {
     local bytes
 
     if moIsStandalone bytes "$2" "$4" "$5"; then
+        # shellcheck disable=SC2206
         bytes=( $bytes )
         echo -n "${2:0:${bytes[0]}}"
         local "$1" && moIndirect "$1" "${4:${bytes[1]}}"
@@ -972,11 +1090,14 @@ moTrimWhitespace() {
 # Returns nothing.
 moUsage() {
     grep '^#/' "${MO_ORIGINAL_COMMAND}" | cut -c 4-
+    echo ""
+    echo "MO_VERSION=$MO_VERSION"
 }
 
 
 # Save the original command's path for usage later
 MO_ORIGINAL_COMMAND="$(cd "${BASH_SOURCE[0]%/*}" || exit 1; pwd)/${BASH_SOURCE[0]##*/}"
+MO_VERSION="2.2.0"
 
 # If sourced, load all functions.
 # If executed, perform the actions as expected.

run-tests

@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 
+# shellcheck disable=SC1091
 . ./mo
 PASS=0
 FAIL=0
@@ -18,13 +19,16 @@ for TEST in tests/*.expected; do
             "${BASE}.sh"
         else
             # Fall back to using .env and .template
+            # shellcheck disable=SC1090
             . "${BASE}.env"
             echo "Do not read this input" | mo "${BASE}.template"
         fi
     ) | diff -U5 - "${TEST}" > "${BASE}.diff"
 
-    if [[ $? -ne 0 ]]; then
-        echo "FAIL"
+    statusCode=$?
+
+    if [[ $statusCode -ne 0 ]]; then
+        echo "FAIL (status code $statusCode)"
         FAIL=$(( FAIL + 1 ))
     else
         echo "ok"

tests/double-hyphen.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
 # This should display a message indicating that the file --help
 # could not be found.  It should not display a help messsage.
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 ../mo -- --help 2>&1

tests/fail-not-set-file.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 unset __NO_SUCH_VAR
 POPULATED="words" EMPTY="" ../mo --fail-not-set ./fail-not-set-file.template 2>&1
 

tests/fail-not-set.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 unset __NO_SUCH_VAR
 POPULATED="words" EMPTY="" ../mo --fail-not-set 2>&1 <<EOF
 Populated: {{POPULATED}};

tests/fail-on-function.expected

@@ -0,0 +1 @@
+Fail on function? Function 'failFunction' with args () failed with status code 1

tests/fail-on-function.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+cd "${0%/*}" || exit 1
+
+failFunction() {
+    false
+}
+
+# Must be sourced to use functions
+# shellcheck disable=SC1091
+. ../mo
+mo --fail-on-function 2>&1 <<EOF
+Fail on function? {{failFunction}}
+EOF
+
+if [[ $? -ne 1 ]]; then
+    echo "Did not return 1"
+fi

tests/false-is-empty-arg.sh

@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 USER=j.doe ADMIN=false ../mo --false false-is-empty-arg.template

tests/function-args-read.env

@@ -0,0 +1,3 @@
+testArgs() {
+    echo "$MO_FUNCTION_ARGS"
+}

tests/function-args-read.expected

@@ -0,0 +1,4 @@
+No args: [] - done
+One arg: [one] - done
+Multiple arguments: [aa bb cc 'x' " ! {[_.|] - done
+Evil: [bla; cat /etc/issue] - done

tests/function-args-read.template

@@ -0,0 +1,4 @@
+No args: [{{testArgs}}] - done
+One arg: [{{testArgs one}}] - done
+Multiple arguments: [{{testArgs aa bb cc 'x' " ! {[_.| }}] - done
+Evil: [{{testArgs bla; cat /etc/issue}}] - done

tests/function-args.env

@@ -0,0 +1,13 @@
+name=Willy
+MO_ALLOW_FUNCTION_ARGUMENTS=true
+
+pipeTo() {
+    cat | "$1"
+}
+
+testArgs() {
+    printf "%d" "$#"
+
+    # Display all arguments
+    printf " %q" ${@+"$@"}
+}

tests/function-args.expected

@@ -0,0 +1,4 @@
+No args: 0 '' - done
+One arg: 1 one - done
+Getting name in a string: 1 The\ name\ is\ Willy - done
+Reverse this: edcba

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}}

tests/function.env

@@ -1,5 +1,5 @@
 name=Willy
 wrapped() {
-    # The final newline is eaten by mo
-    echo "<b>$1</b>"
+    # This eats the newline in the content
+    echo "<b>$(cat)</b>"
 }

tests/function.expected

@@ -1,2 +1 @@
-<b>  Willy is awesome.
-</b>... this is the last line.
+<b>  Willy is awesome.</b>... this is the last line.

tests/help.expected

@@ -9,9 +9,20 @@ Learn more about mustache templates at https://mustache.github.io/
 
 Simple usage:
 
-   mo [--false] [--help] [--source=FILE] filenames...
+   mo [OPTIONS] filenames...
 
---fail-not-set - Fail upon expansion of an unset variable.
---false        - Treat the string "false" as empty for conditionals.
---help         - This message.
---source=FILE  - Load FILE into the environment before processing templates.
+Options:
+
+   -u, --fail-not-set
+         Fail upon expansion of an unset variable.
+   -x, --fail-on-function
+         Fail when a function returns a non-zero status code.
+   -e, --false
+         Treat the string "false" as empty for conditionals.
+   -h, --help
+         This message.
+   -s=FILE, --source=FILE
+         Load FILE into the environment before processing templates.
+         Can be used multiple times.
+
+MO_VERSION=2.2.0

tests/help.sh

@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 ../mo --help

tests/invalid-option.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
 # This should display a message indicating that the file --something
 # could not be found.
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 ../mo --something 2>&1

tests/partial-missing.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 ../mo partial-missing.template 2>&1
 
 if [[ $? -ne 1 ]]; then

tests/source-bad-file.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 echo "Do not display this" | ../mo --source=invalid 2>&1
 
 if [[ $? -ne 1 ]]; then

tests/source-multiple-1.vars

@@ -0,0 +1,2 @@
+export A=from1
+export B=from1

tests/source-multiple-2.vars

@@ -0,0 +1,2 @@
+export B=from2
+export C=from2

tests/source-multiple.expected

@@ -0,0 +1,3 @@
+A: from1
+B: from2
+C: from2

tests/source-multiple.sh

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+cd "${0%/*}" || exit 1
+cat <<EOF | ../mo --source=source-multiple-1.vars --source=source-multiple-2.vars
+A: {{A}}
+B: {{B}}
+C: {{C}}
+EOF

tests/source-no-file.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 echo "Do not display this" | ../mo --source= 2>&1
 
 if [[ $? -ne 1 ]]; then

tests/source.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-cd "${0%/*}"
+cd "${0%/*}" || exit 1
 cat <<EOF | ../mo --source=source.vars
 {{VAR}}
 {{#ARR}}

tests/source.vars

@@ -1,4 +1,5 @@
 export VAR=value
 export ARR=(1 2 3)
 declare -A ASSOC_ARR
-export ASSOC_ARR=([a]=AAA [b]=BBB)
+# Can not export associative arrays, otherwise they turn into indexed arrays
+ASSOC_ARR=([a]=AAA [b]=BBB)