Added function to handle argument parsing.

Shrikant Sharat
1 parent 0b4fbaaf6a
Showing 2 changed files with 160 additions and 0 deletions Side-by-side Diff
antigen.zsh
tests/arg-parser.t
@@ -364,6 +364,118 @@ antigen () {
     "antigen-$cmd" "$@"
 }
  
+-antigen-parse-args () {
+    # An argument parsing functionality to parse arguments the *antigen* way :).
+    # Takes one first argument (called spec), which dictates how to parse and
+    # the rest of the arguments are parsed. Outputs a piece of valid shell code
+    # that can be passed to `eval` inside a function which creates the arguments
+    # and their values as local variables. Suggested use is to set the defaults
+    # to all arguments first and then eval the output of this function.
+
+    # Spec: Only long argument supported. No support for parsing short options.
+    # The spec must have two sections, separated by a `;`.
+    #       '<positional-arguments>;<keyword-only-arguments>'
+    # Positional arguments are passed as just values, like `command a b`.
+    # Keyword arguments are passed as a `--name=value` pair, like `command
+    # --arg1=a --arg2=b`.
+
+    # Each argument in the spec is separated by a `,`. Each keyword argument can
+    # end in a `:` to specifiy that this argument wants a value, otherwise it
+    # doesn't take a value. (The value in the output when the keyword argument
+    # doesn't have a `:` is `true`).
+
+    # Arguments in either section can end with a `?` (should come after `:`, if
+    # both are present), means optional. FIXME: Not yet implemented.
+
+    # See the test file, tests/arg-parser.t for (working) examples.
+
+    local spec="$1"
+    shift
+
+    local code=''
+
+    --add-var () {
+        test -z "$code" || code="$code\n"
+        code="${code}local $1='$2'"
+    }
+
+    local positional_args="$(echo "$spec" | cut -d\; -f1)"
+    local positional_args_count="$(echo $positional_args |
+            awk -F, '{print NF}')"
+
+    # Set spec values based on the positional arguments.
+    local i=1
+    while ! [[ -z $1 || $1 == --* ]]; do
+
+        if (( $i > $positional_args_count )); then
+            echo "Only $positional_args_count positional arguments allowed." >&2
+            echo "Found at least one more: '$1'" >&2
+            return
+        fi
+
+        local name_spec="$(echo "$positional_args" | cut -d, -f$i)"
+        local name="${${name_spec%\?}%:}"
+        local value="$1"
+
+        --add-var $name "$value"
+
+        shift
+        i=$(($i + 1))
+    done
+
+    local keyword_args="$(echo "$spec" | cut -d\; -f2 | tr , '\n')"
+    local keyword_args_count="$(echo $keyword_args | awk -F, '{print NF}')"
+
+    # Set spec values from keyword arguments, if any. The remaining arguments
+    # are all assumed to be keyword arguments.
+    while [[ $1 == --* ]]; do
+        # Remove the `--` at the start.
+        local arg="${1#--}"
+
+        # Get the argument name and value.
+        if [[ $arg != *=* ]]; then
+            local name="$arg"
+            local value=''
+        else
+            local name="${arg%\=*}"
+            local value="${arg#*=}"
+        fi
+
+        # The specification for this argument, used for validations.
+        local arg_line="$(echo "$keyword_args" | grep -m1 "^$name:\??\?")"
+
+        # Validate argument and value.
+        if [[ -z $arg_line ]]; then
+            # This argument is not known to us.
+            echo "Unknown argument '$name'." >&2
+            return
+
+        elif (echo "$arg_line" | grep -qm1 ':') && [[ -z $value ]]; then
+            # This argument needs a value, but is not provided.
+            echo "Required argument for '$name' not provided." >&2
+            return
+
+        elif (echo "$arg_line" | grep -vqm1 ':') && [[ ! -z $value ]]; then
+            # This argument doesn't need a value, but is provided.
+            echo "No argument required for '$name', but provided '$value'." >&2
+            return
+
+        fi
+
+        if [[ -z $value ]]; then
+            value=true
+        fi
+
+        --add-var "${name//-/_}" "$value"
+        shift
+    done
+
+    echo "$code"
+
+    unfunction -- --add-var
+
+}
+
 # Echo the bundle specs as in the record. The first line is not echoed since it
 # is a blank line.
 -antigen-echo-record () {
@@ -0,0 +1,48 @@
+Helper alias.
+
+  $ alias parse='-antigen-parse-args "url?,loc?;btype:?,no-local-clone?"'
+
+No arguments (since all are specified as optional).
+
+  $ parse
+   (glob)
+
+One positional argument.
+
+  $ parse name
+  local url='name'
+
+Two arguments.
+
+  $ parse url location
+  local url='url'
+  local loc='location'
+
+Three arguments.
+
+  $ parse url location crap
+  Only 2 positional arguments allowed.
+  Found at least one more: 'crap'
+
+Keywordo magic.
+
+  $ parse url location --btype=1 --no-local-clone
+  local url='url'
+  local loc='location'
+  local btype='1'
+  local no_local_clone='true'
+
+Unknown keyword argument.
+
+  $ parse --me=genius
+  Unknown argument 'me'.
+
+Missed value for keyword argument.
+
+  $ parse --btype
+  Required argument for 'btype' not provided.
+
+Provide value for keyword argument, that shouldn't be there.
+
+  $ parse --no-local-clone=yes
+  No argument required for 'no-local-clone', but provided 'yes'.
...	...	@@ -364,6 +364,118 @@ antigen () {
364	364	"antigen-$cmd" "$@"
365	365	}
366	366
	367	+-antigen-parse-args () {
	368	+ # An argument parsing functionality to parse arguments the antigen way :).
	369	+ # Takes one first argument (called spec), which dictates how to parse and
	370	+ # the rest of the arguments are parsed. Outputs a piece of valid shell code
	371	+ # that can be passed to `eval` inside a function which creates the arguments
	372	+ # and their values as local variables. Suggested use is to set the defaults
	373	+ # to all arguments first and then eval the output of this function.
	374	+
	375	+ # Spec: Only long argument supported. No support for parsing short options.
	376	+ # The spec must have two sections, separated by a `;`.
	377	+ # '<positional-arguments>;<keyword-only-arguments>'
	378	+ # Positional arguments are passed as just values, like `command a b`.
	379	+ # Keyword arguments are passed as a `--name=value` pair, like `command
	380	+ # --arg1=a --arg2=b`.
	381	+
	382	+ # Each argument in the spec is separated by a `,`. Each keyword argument can
	383	+ # end in a `:` to specifiy that this argument wants a value, otherwise it
	384	+ # doesn't take a value. (The value in the output when the keyword argument
	385	+ # doesn't have a `:` is `true`).
	386	+
	387	+ # Arguments in either section can end with a `?` (should come after `:`, if
	388	+ # both are present), means optional. FIXME: Not yet implemented.
	389	+
	390	+ # See the test file, tests/arg-parser.t for (working) examples.
	391	+
	392	+ local spec="$1"
	393	+ shift
	394	+
	395	+ local code=''
	396	+
	397	+ --add-var () {
	398	+ test -z "$code" \|\| code="$code\n"
	399	+ code="${code}local $1='$2'"
	400	+ }
	401	+
	402	+ local positional_args="$(echo "$spec" \| cut -d\; -f1)"
	403	+ local positional_args_count="$(echo $positional_args \|
	404	+ awk -F, '{print NF}')"
	405	+
	406	+ # Set spec values based on the positional arguments.
	407	+ local i=1
	408	+ while ! [[ -z $1 \|\| $1 == --* ]]; do
	409	+
	410	+ if (( $i > $positional_args_count )); then
	411	+ echo "Only $positional_args_count positional arguments allowed." >&2
	412	+ echo "Found at least one more: '$1'" >&2
	413	+ return
	414	+ fi
	415	+
	416	+ local name_spec="$(echo "$positional_args" \| cut -d, -f$i)"
	417	+ local name="${${name_spec%\?}%:}"
	418	+ local value="$1"
	419	+
	420	+ --add-var $name "$value"
	421	+
	422	+ shift
	423	+ i=$(($i + 1))
	424	+ done
	425	+
	426	+ local keyword_args="$(echo "$spec" \| cut -d\; -f2 \| tr , '\n')"
	427	+ local keyword_args_count="$(echo $keyword_args \| awk -F, '{print NF}')"
	428	+
	429	+ # Set spec values from keyword arguments, if any. The remaining arguments
	430	+ # are all assumed to be keyword arguments.
	431	+ while [[ $1 == --* ]]; do
	432	+ # Remove the `--` at the start.
	433	+ local arg="${1#--}"
	434	+
	435	+ # Get the argument name and value.
	436	+ if [[ $arg != = ]]; then
	437	+ local name="$arg"
	438	+ local value=''
	439	+ else
	440	+ local name="${arg%\=*}"
	441	+ local value="${arg#*=}"
	442	+ fi
	443	+
	444	+ # The specification for this argument, used for validations.
	445	+ local arg_line="$(echo "$keyword_args" \| grep -m1 "^$name:\??\?")"
	446	+
	447	+ # Validate argument and value.
	448	+ if [[ -z $arg_line ]]; then
	449	+ # This argument is not known to us.
	450	+ echo "Unknown argument '$name'." >&2
	451	+ return
	452	+
	453	+ elif (echo "$arg_line" \| grep -qm1 ':') && [[ -z $value ]]; then
	454	+ # This argument needs a value, but is not provided.
	455	+ echo "Required argument for '$name' not provided." >&2
	456	+ return
	457	+
	458	+ elif (echo "$arg_line" \| grep -vqm1 ':') && [[ ! -z $value ]]; then
	459	+ # This argument doesn't need a value, but is provided.
	460	+ echo "No argument required for '$name', but provided '$value'." >&2
	461	+ return
	462	+
	463	+ fi
	464	+
	465	+ if [[ -z $value ]]; then
	466	+ value=true
	467	+ fi
	468	+
	469	+ --add-var "${name//-/_}" "$value"
	470	+ shift
	471	+ done
	472	+
	473	+ echo "$code"
	474	+
	475	+ unfunction -- --add-var
	476	+
	477	+}
	478	+
367	479	# Echo the bundle specs as in the record. The first line is not echoed since it
368	480	# is a blank line.
369	481	-antigen-echo-record () {
...	...	@@ -0,0 +1,48 @@
	1	+Helper alias.
	2	+
	3	+ $ alias parse='-antigen-parse-args "url?,loc?;btype:?,no-local-clone?"'
	4	+
	5	+No arguments (since all are specified as optional).
	6	+
	7	+ $ parse
	8	+ (glob)
	9	+
	10	+One positional argument.
	11	+
	12	+ $ parse name
	13	+ local url='name'
	14	+
	15	+Two arguments.
	16	+
	17	+ $ parse url location
	18	+ local url='url'
	19	+ local loc='location'
	20	+
	21	+Three arguments.
	22	+
	23	+ $ parse url location crap
	24	+ Only 2 positional arguments allowed.
	25	+ Found at least one more: 'crap'
	26	+
	27	+Keywordo magic.
	28	+
	29	+ $ parse url location --btype=1 --no-local-clone
	30	+ local url='url'
	31	+ local loc='location'
	32	+ local btype='1'
	33	+ local no_local_clone='true'
	34	+
	35	+Unknown keyword argument.
	36	+
	37	+ $ parse --me=genius
	38	+ Unknown argument 'me'.
	39	+
	40	+Missed value for keyword argument.
	41	+
	42	+ $ parse --btype
	43	+ Required argument for 'btype' not provided.
	44	+
	45	+Provide value for keyword argument, that shouldn't be there.
	46	+
	47	+ $ parse --no-local-clone=yes
	48	+ No argument required for 'no-local-clone', but provided 'yes'.